Tony,
You can start off with a hot air popcorn popper. They only do about 3 oz. at a time, and they tend to burn out quickly, but it will get you started.
After going through half a dozen of the units, I finally ended up with a Behmor 1600 drum roaster. At the going rate of $299, it may sound expensive, but it does a full pound at a time, and is far less expensive than many other drum roasters.
Do a search for Sweet Maria's. Best green beans on the planet. Check out their Library while you are there for all kinds of tips on how to home roast. They even have an entire section dedicated to roasting with a hot air popper.
A word of warning. Once you start home roasting, you'll never be able to go back.