UNIX for Dummies Questions & Answers

for more than 5 years i have used windows based operating systems and hardwear, but recently i have decided to venture into the world of unix systems. very recently infact- i dont own a unix system yet and was wondering about hardwear..
i was planning on buying a second hand system from ebay because of the price, which i could upgrade if nessacary. most of the systems are sold without monitors, and i was wondering if there were particular monitors which had to be used with unix systems? if anyone could help i just need general advice on what to buy, im totally clueless but want to leave windows in the bin where it belongs. any help would be much appreciated but no slatings please (everyone starts somewhere!)
also, which ISP is reccomended?

i suggest that you getany ibm compatible system, just like your windows-based system. then install linux on it. well, linux is create for unix to run on pc...