Ah, that's an interesting question. Stuff certainly can get expensive, especially when loading up mostly from scratch.One always can find good buys on certain things, so I don't think it useful for me to make up a list that includes a specific parka, sleeping bag, stuff like that. Instead, here's some advice on ensuring you can find good buys on just about anything:
Shop "house" brands. Name-brand stuff is great, but remember you're paying for a distributor to get the stuff into the stores. Companies such as L.L. Bean, REI, and Eastern Mountain Sports all have their own "house" brand stuff. Much of it is very good, some of it is comparable to or better than name-brand items. Case in point: REI's Shuksan Jacket with eVent ($299) matches well with pieces that cost $100 more. Bean's Super 200 Cresta jacket is made from Polartec Wind Pro yet costs only $59, half what most good fleece pieces run. And Eastern Mountain Sports' Mountain Light 20-degree sleeping bag has 750-fill down and a top-flight Pertex shell, yet sells for $239, again, about $100 less than comparable name-brand bags.
Shop overstock stores. Thanks to the Internet, you can find all sorts of good deals on outdoor gear. The granddaddy of Web-based "closeout" stores is Sierra Trading Post, where I've bought a number of things over the years. Need some good boots? Sierra has Asolo Power Matic 400s for $155—that's $75 less than suggested retail. How about a pack? Gregory's Z55 for $130—$70 off retail. You'll also often find last year's stuff available online. If it was good in 2009, there's no way it improved that much in one year. So buy the "obsolete" stuff and save $$. Other great sites include Department of Goods and REI Outlet
Hit outlet malls. You'll often find The North Face, Columbia Sportswear, L.L. Bean, and Helly-Hansen in outlet malls. That'll usually save you 30 percent or more over retail.
Use Craigslist. I'm not sure I'd buy a used rope. But almost anything else, why not? There's a guy near me selling an MSR Whisperlite International for $44—that stove is $90 at retail.
So there you are. Go forth, be frugal, equip well.