Over here in the States we have garage sales, which I'm assuming are the same sort of thing... not always in the garage, and not all in one place, usally. I like to hit the sales for entertainment, but it is possible to find some good deals.
I bought the pc i'm using now at a garage sale for 5 bucks. They were paranoids and pulled the HD, but not bad for a 2.1 gHz Athlon. Works great. Got one of the monitors for 8 bucks, the other was free (freecycle)... While out hitting the sales couple years back, I found a guy with a baker's rack in the yard and a "free stuff" sign on it.. I got a nice scanner with an ADF unit.
You can get burned though... I took a chance on some bare HDs once. Crash!... got some nice magnets out of 'em. ;-)