Look at the completed listings for these items as well as feedback on like items from the seller. it comes down to knowing the item you are buying and a little bit of a gamble.
Do some research.
You are trading your time(ie.research)for savings.
IBM T22 laptop,900mhz p3,20g hdd,512mb ram
IBM Netvista M42 40g hdd,1.8g p4,512mb ram
IBM Netvista 933 mhz p3,10g hdd,256 mb ram
Winbook laptop 400mhz p2
Dell 4600 2.8g cpu,120g hdd,256 mb ram(On bottom of list where pc of **** belongs)
768/128 DSL w/LAN(wireless G)