Indoor biking - Trainer vs. Exercise bike

[dylan's alias]

I spent this summer moving and barely got on my bike. I will have more time in the next few months, but outside in Chicago is out of the question. So, does anyone have any advice on my indoor options? I'd rather not spend a ton of money but I would like to get a quality product that will last. My only experience with exercise bikes have been in the gym. Do home models have programmable resistance that changes through the ride? Do trainers? Basically, I'm clueless, so any advice would be greatly appreciated.