Download fink and you can get a lot of the standard *nix tools.
--
As for Macs being expensive, well it depends what you are comparing it with, the PC market has a very wide range of prices including machines which cost vastly *more* than macs. If you compare to similar products from similar PC makers there isn't much if any price difference, in fact Macs may work out costing less.
I've been playing with my parents cheap PC and I can say I'm very glad I'm not using a PC. It's specifications are supposedly higher but my G4 but it does not require 10 minutes to boot, run slower than a P266, take 30 seconds to draw a window or crash if you try printing while using the internet.
This is a Celeron 2.6GHz which should not be anywhere near that bad but the manufacturer made their machine cheap by only including 128MB RAM, XP is evidently not happy with this, not all the malware which has managed to install itself despite my dad having a virus killer, Adaware, Spybot etc.
OS X is pretty hungry as well but 256 MB should be fine if you're not doing a lot at once.
It's simple really, you get what you pay for.