The future (in my opinion) are the autonomous drones. I would invest my programming energy in learning how those work. In fact a few promising projects go in this direction.
E.g. HEXO+, AirDog (main purpose, attach a GoPro and use them to film). I read somewhere that they may be based on the ArduCopter project.
So the cheapest option seems to be the AR.drone 2.0, which is also very popular and you may even find used models on amazon, for even 190 US$!
Which one should you choose?
Parrot AR.Drone 2.0 SDK in C#/.NET
Ruslan-B/AR.Drone on GitHub - The AR.Drone 2.0 controlling library for C#/.NET and Mono, with video support. Built over the original AR.Drone SDK 2.0.1 - using lastest drone firmware.
If the cost is an issue, you may wanna buy the cheapest option and begin learning from there. Go for AR.Drone 2.0 and try the AR.Drone library by Ruslan-B. It may be even easier to learn (just my opinion - need to test). If you already own an AR.Drone 2.0 or can borrow one from a friend it makes sense to give this a try.
To consider: the last commit on Ruslan-B code was on August, 26th 2014. Maybe the community and support for this may not be that big. But the project looks mature and stable (to check) so it may not be a big issue. Eventually, questions and support can be found on stackoverflow.
If you wanna learn the cool and advanced stuff directly, check the ArduPilot/APM project. The drone will cost more money, but on the other hand the projects look more active, and there is a big community.
To consider: The main flight code for ArduPilot/APM is written in C++. Support tools are written in a variety of languages, most commonly in python. So far only the MissionPlanner is available in C#. Check what each project does, and see if it's ok for you.
Skeye Nano vs. Cheerson CX-10 vs. Cheerson CX-10A Headless vs. (other or no brand) Nano drone: Cheerson CX-10 wins! If you wanna buy a cheap Nano drone, Cheerson CX-10 the one to buy! You may think that the 10A is better but it's not. It's just marketing, the headless function is kinda useless. I own both, I can tell you. Check also the videos (a guy compared both of them and is telling the same: the CX-10A is slower).
Update July 2017: if you are interested in the model with the camera, check the Cheerson CX-10C, for only 24 USD (Skye Nano version: 99 USD if you like to pay more...)
Update September 2015: now you can order the Cheerson CX-10C, which includes a 0.3 MP camera! I still think that the CX-10 is the best, but hei if you wanna take some low quality pictures just for fun, why not.
Cheerson CX-10, the original
The Cheerson CX-10 exists since a while. It can be bought for less than 20 USD from banggood.com and it's available in different colors: orange, green, blue. Orange is my favorite.
This is the new model and it's headless, which means that you don't have to position it in the flying direction before the take off. It orginally costes a few bucks more but now it's being sold at the same price as the CX-10, probably because they realizes nobody wants it :). It's available in different, fancy new colors (black, white, silver, gold with some tribal logo on it). Update after receiving and testing it: I never use the headless mode (you need to specifically activate it so if you are like me you won't do it, you will probably just turn it on and fly it, so you would not "benefit" the headless mode). So if you wanna buy this one instead of the original CX-10, it's probably because of the design/color (black is kinda cool). But for a better flying experience, buy the CX-10 which is a bit more reactive. I like both of them but the CX-10 is better in my opinion.
In the Cheerson CX-10/CX-10A package you get (besides quad, transmitter, charging USB cable) only 4 spare propellers. 2 turn clockwise, 2 counter clockwise. The CX-10 transmitter is compatible with the CX-10A and vice-versa. I have 2 different models but only use one transmitter, it works just fine. I can also fly one and a friend of mine flies the other one with the other transmitter. No problem, they don't interfere if you were wondering.
Important, when you order your mini quad, you can choose which mode to control it. In USA (and EU): people in the RC community generally use Mode 2, left hand throttle. So if you wanna get familiar with the "standard", buy the model with the mode 2 transmitter.
After playing for a while with my Cheerson CX-10 I think I can recommend to beginners to buy some spare parts, like these:
Especially when playing inside, collisions are almost inevitable. When the copter falls down violently, the propellers can be turned a bit (they can be fixed) but after several collisions they break. Buy the protection cover, you'll never need to replace propellers anymore.
Cheerson CX-10C with camera
This is basically the same as the CX-10, but with a 0.3 MP camera. 0.3 Mega pixel is really low quality, don't even bother buying this, you can take better selfies with your phone, really. But in case you wanna give it a try:
If you are here because you saw the Skeye nano drone - "World’s Smallest Quadcopter" for a special price (limited offer) and you were wondering if it's worth to buy: DON'T buy it. I sadly ordered one from the gizmag store and unluckily the order is non-refundable. See a screenshot of this "limited offer" taken from gizmag:
Check a video of the Skeye Nano. As you can see, it's practically identical to the Cheerson CX-10.
The Skeye nano can be found on gizmag.com, stacksocial.com, androidauthority.com etc. (all webshops look the same) for a "limited offer" 41% discount (or something like that), so for 35 USD (update: last time I saw "sale ends in 4 days", now -a week after- I see "sale ends in 6 days", seems it's just a marketing way to attract customers...). On trndlabs.com it can be found at the official price of 49 USD. For this price you can buy 3 Cheerson CX-10! Quite a rip-off!
Same technical specifications and same design. At the time of writing, it's being sold at different shops (see above) but nobody wrote yet a comparison review between the two models. Quite funnily the special offer will be gone in a few days.
The order is non-refundable. I ordered one myself and I wrote this post to warn users not to make the same mistake as I was quite frustrated myself. I don't usually write rants. This is just to open your eyes. If you wanna buy the skeye, feel free.
Personally, I bought also a Cheerson CX-10 at and a Cheerson CX-10A at banggood (see links above) so in the end I'll have 3 models for an average of 25 USD.
LinkTasker is a tool to periodically process URLs and do something with them, e.g. sending an e-mail containing a file, or inline HTML of a portion of a website if you insert a CSS path for it.
I personally need to monitor the weather and in some cases I need to save a weather image every hour, for history purposes or a debriefing.
To create a task in LinkTasker for my example it's extremely easy: insert the image URL and specify from when to when to call it, and how often. You can also set a maximum times of executions.
LinkTasker will download and check the URL in the chosen interval. If the file/page has changed, LinkTasker will send you an e-mail, else not.
If the URL is a file, you can expect to get the file attached to the e-mail.
You can even monitor a news website. You can easily identify which part of the newspaper contains the most important news, or an alarm or something like that, that changes periodically. You insert the URL of the page, the CSS path of that element and LinkTasker will send you an e-mail of that part of the page only. If you don't specify the CSS path, you will get the entire HTML page in attachment.
How to get the CSS path of a specific part of a page
To get the CSS path of a specific part/area of a page of your interest, with Chrome it's quite easy. Press the F12 key, this will display the Developer Tools > On the top left, click the Lope icon > click the area of your interest > Right click on the element containing it and select Copy CSS path > The CSS path will be copied in the clipboard. You can paste it in the "CSS Path" field when you create a LinkTasker task. See the following screenshot:
Competition / similar services
Changedetection.com lets you monitor a URL and it automatically sends you an e-mail when something changes. It's a cool service! I also use changedetection one to see what changes in little, almost never updated websites.