Building electroncs is one of the coolest hobbies because you can get most of your parts for FREE. Yes, FREE. Including free shippng. You just need to know where to go and how to ask for them. Many companies have "sample parts" available and the ones that don't can usually be talked into it if you know how to approach them.
Analog devices makes a huge variety of semiconductors. They also have MEMS parts (Micro Electrical Mechanical System) such as accelerometers, gyroscopes and other cool and useful parts.
When accelerometers first arrived on their product line, they were expensive - about $40/each for a part that now costs about $4. But at the time I wanted to get my hands on one. Actually, I had to have THREE of them if I wanted to do 3-axis. So I called them up and talked to a few people and managed to finagle 3 accelerometers for free. Sometimes you have to get on the phone and sound like you work for a legit company, and tell them the project you are working on is projected to use 100,000 parts a year. That's the main thing these companies want to hear - that you are working on a project of some scale. They aren't interested so much in selling 1,000 parts. They are interested in selling 100,000 parts. Tell them what they want to hear and you'll get some free parts.
See what you can get from them here: http://www.analog.com/en/content/samples/fca.html