Bike trainers work too!
I have five bikes, so instead of a spin bike purchase, I bought a trainer. It made sense considering I am riding my fitted-to-me road bike or change it out with one of my mountain bikes. So there is that option for those who already have bikes and maybe just want to spend $200 to $750 on a trainer. There are lots of different types of trainers too, and I settled on one with a natural motion just like riding outside (thanks MeowRacer). I download a lot from Motiontraxx.com even though its designed for running, works just as well with a trainer or elliptical when its 165 bpm or less. I would buy a spin dvd from Cathe asap!