My rides, in order of expense -
Mid-Eighties, Steve Bauer 18sp. MTB/Tourer? My husband picked it up for me out of the Buy and Sell for fifty bucks. I put $10.oo plastic fenders on it, replaced one inner tube and got a set of bottom of the line panniers for Christmas.
5sp Venture Caprice. Picked it up last Wednesday during Recycling week. It's in very good shape. I put a five dollar inner tube in the back tire this morning and rode it to church.
'74 Triumph single speed. I picked up a rear fender and rack for it during the reycycling festivities, but so far it hasn't actually cost me anything. A co-worker's mother kicked it out of their garage and he gave it to me.
That's all about as cheap as you can get, but I'm on one or the other of 'em every day. I can hardly call my ride to work a '"commute", since it only takes fifteen minutes or less, but I don't drive so I also use 'em to shop etc.
The Triumph is probably my favorite. I can beat my sixteen year old son with it when he's riding the Bauer! Uphill!!
I'd be afraid to actually go out on a bike that cost more than my rent. I've had new or near new bikes a couple of times and of course they got swiped. I'm really a lot more comfortable with my oldies. I like well used things, with personality.