I have a "Wallstreet" actually its the later version, different code name. I bought it used from someone I know. The hard drive was dead and the person didn't want to fix it. He bought a new iBook.
Took it off his hands about a year ago, put a 30GB HD in it. It had 192 MB RAM already, I'm going to put more before long. It has 1MB Level 2 cache and a 266 mhz. Total cost so far about $450.
Anyway the thing about these is the hinges for the screens. Mine has a 14.1". The hinges will break, they are a poor design. I replaced mine and now no problems. If you have one with bad hinges, don't go to Apple or one of their dealers. They will try to charge you $300-350 to repair them. It is a rip off. The hinges cost $40 and if you have the time and the willingness you can replace them yourself. It isn't easy but it can be done if you are careful. The main problem is buying the hinges, they are hard to find. I got my from a computer dealer, I won't say who here though, since Apple doesn't want non-Apple dealer selling and replacing them.
If you need a G3 powerbook it is a good buy if you can find a cheap one. No USB or firewire though. The Pismo is an even better buy if you can find one for less than $500.