14b's go for $150 or less all the time. I bought my big 16g for $300. You will need some supporting mods to get all the power out of a 14b, but yes, you can run any turbo on stock fuel... don't expect much more power. $150 isn't bad to start out small. I believe 95 GSXracer said a rewired stock 2g pump and stock 450cc injectors maxed out the 14b... but you have to be careful. If you are going to buy a larger turbo, be ready to get the supporting mods to get the most power out of it.
longemoco: there is a long thread about turbocharging an RS. Yes, the T25 is pretty good for it.