Yep, picked up a couple of mid 2000s zaskars for not much more than 100 before now. I suppose it depends what you want and how long you are prepared to spend looking
Also try your local recycling center and leave a card with one of the staff saying what you are looking for. Seen an alloy one and other decent mid range bikes stacked up in Finchley ( Summers Ln) last time i was there.