i had the same feeling a few months ago. couldn't wait anymore, so i got a set of rollers via craigslist for $80. not the best, i'm sure, but they work.

it took me about a week's worth of riding to get used to them. i'd say DONT start with a stool or wall. the key to riding without falling is:
(1) PEDAL FASTER when you feel like you're going to fall
(2) LOOK FORWARD, not down.
and you'll stay up.

also, i have to recommend the 1UP trainer. it's S I L E N T.