How do I get started in roasting my own beans at home? I'd like to experiment with roasting my own beans at home.

I'd like to keep the equipment requirements as basic as possible. No fancy gizmos or machines. I have a gas stove.
By far the easiest way to start at home roasting is with a hot air popcorn popper.  You can get a used one for $5 at a thrift store or pay approximately $20 new for one.  Or perhaps you already have an unused one laying around.  There are also people and websites out there showing you great ways to modify or make them better with cheap addon parts or hacks.  

I started with one and after I decided I was hooked I spent the money on a commercial made roaster, but I learned most of what I know with a hot air popper in my front yard.  I think the biggest issue for stove top roasting is the smoke.  If you don't have great ventilation in your house over your stove, accidental overroasts and dark roasts become a major problem.