I know I'm not the norm here, but good deals can be found just about anywhere if you look for them.
About 30% of my gear came from the local dump, where a friend who works there looks for it before it gets crushed. To date he has saved tents, packs, clothing, poles, and even a simmerlite stove from the crusher.
Another 30% came from Goodwill or the Salvation Army. If you look often enough you can find Gore-Tex jackets and pants, fleece, base layers (just picked up some Bergelene for $1), and just about anything else at a fraction of the cost. I've never paid more than $20 for anything, except the 5Mp camera for $28, but it was worth it.
About 15% came from lawn sales.
Probably 10% came from eBay, but nothing was over 60% of new.
And the last 15% came from various retail stores such as LL Bean, EMS, REI, IME, Ragged Mountain, and anywhere else that was having a sale, very rarely do I pay full price for anything.
I keep a tally of the camping weights on my gear, and so far I've paid an average of 11% of the cost of new. Having good gear doesn't need to break the bank.