It is really incredible the bikes one can find keeping an eye on Freecycle, bouncing around garage sales, and bike auctions around a college campus after the semester ends. Or just asking, "hey you want that bike I've seen hanging unused in your garage for the last few years?"
Free ones I especially like.

After a good refurbing job...
And, two more freebies to clean/lube/refurb
This is a new commuter I'm building up from free bikes & parts from many of them.
I've collected a bunch more...
But, I really like the price spent so far on about 10 bikes to play with..... $35 total.
I hate/love new obsessions.
Dr. Joe