Note, unless you are already working with a different microprocessor or board level electronics, the cost of an Arduino itself is only part of the cost. To get started, you should think of getting one of the add-on starter kits that provide lots of the things you will need initially. To some extent, this depends on what you are interested in doing with the Arduino. You don't have to buy everything at once, but it is helpful to have something that you can do when you get the Arduino.
There is an official Arduino starter kit, but it is in short supply, and I think it is expensive enough that most of us would have to think twice about getting it. On the other hand, it looks like well documented (it comes with a book and all of the parts are clearly labeled). I bought an intermediate kit from a US based ebay seller for about $75, and it had an official Uno, breadboard, lots of wires, various sensors, etc. Unfortunately, what it didn't have was documentation, and they just threw all of the components in a few unlabeled plastic bags. In fact, there were several sensors that I didn't know what they were initially, and 6 months later I had need of a force sensor, and discovered it was one of the things in the bag that I had just put aside.
Then there is the issue of branded Arduino or clone. The branded Arduinos are the only ones that the Arduino team makes money off of, and the money obviously pays the staff to come up with new Arduinos. Clones can be much cheaper or come in different packages, but depending on where you get the clones they might have cut corners somewhere.
So lets see what some of my favorite vendors have:
- Arduino-info.com -- $40.50 (US) + s/h for an Uno + shield + basic kit. I like arduino-info because one of the owners (Terry King) posts frequently with helpful information on this site. Note, shipping is from China. My order was something like 1-2 weeks (and Christmas may slow things down for china deliveries in general, unless you live near China) http://arduino-direct.com/sunshop/index.php?l=product_detail&p=302
- Adafruit.com -- $65.00 (US) + s/h for an Uno + sheild + basic kit. While I like Adafruit for a wide variety of components, I tend to think their kit isn't as user friendly to the novice, since it requires soldering the pins to the board, and if you don't have a soldering gun, that is an extra expense. When I was starting out, I couldn't solder, and I tended to go to places that provided all of the components assembled or at least did not require soldering. Adafruit is based in New York, and has fairly fast shipping to the US: http://www.adafruit.com/products/68
- Robotshop.com -- $59.00 (US) + s/h for an Uno + shield + basic kit. While robotshop.com is focused on robots, they have a wide stock of normal microprocessors, including kits for various processors. They are based in Las Vegas, Nevada, USA and have fairly fast shipping within the US: http://www.robotshop.com/dfrobot-dfrduino-arduino-compatible-start-kit.html. For $72.45 they have a kit with electronic bricks that are easier for the novice to use and an LCD screen: http://www.robotshop.com/arduino-electronic-brick-starter-kit.html
So what should be in a basic kit? I think at least the following:
- Basic breadboard
- Selection of jumper wires
- One or more LEDs, preferably of different colors
- Hobby servo
- Maybe infrared remote control and a sensor