Ian, you may need to buy some decent db handles to allow you to load them up with +100lb a piece but, for plates, the owner of a gym where I used to train gave me this tip: put a 'wanted' ad in a local paper rather than just hope you'll spot some for sale in the classifieds. Folks often have weights knocking around in their garages but never get around to selling them. If they see a wanted ad they might just be inclined to pick up the phone and give you a call. You may find you get swamped with offers, which is often what happened to the gym owner I mentioned.
"Be the best that you can be."
Deadlift: 215kg (474lb) - pre-hernia!
Low-bar Back Squat: 190kg (419lb) 16/04/10 @BW ~210lb
Bench: 130kg (287lb) 01/02/13