There is absolutely no reason to buy much of the stuff on this list. Telling someone they need to spend more than a grand to spend a couple of days hiking will surely put them off doing it. I've gone camping with people who had almost none of this stuff and they still had a good time. It was SoCal on the 4th of July, so no worries about rain or cold weather.
Forget the tent, footprint and pack-you can usually borrow a tent or share with someone who already has one; footprints are a waste of money, if you insist on one, make it out of a scrap piece of Tyvek; packs, even good ones are cheap on eBay or Craigslist, so are sleeping bags. You can buy a cheap sleeping pad for $10 at most discount stores (the blue foam one).
I would rather buy a used piece of good gear than something new, but cheap. I've bought a tent, pack, winter parka (the one in my picture), stove, compass, ski boots, rain pants and probably a few things I can't remember offhand off of eBay, Craigslist or here at big discounts, and they are all high quality. A couple of things were new, but a great price, but most were used and about 30-50% of retail. Example, my parka retailed for about $500, I got it for slightly more than half that and it looked brand new when I unpacked it.
Stove-make a soda can stove for almost nothing or get one off eBay or Craigslist.
Clothes-as already noted, thrift shops or big box stores, or online at places like Sierra Trading Post; wool socks are nice, but you don't need to spend $18 a pair, cotton socks are fine for anything except cold, wet, weather. Cheap raingear will work, better yet, plan ahead for your first few trips to avoid bad weather.
Water filter-forget it, either boil your water or use tablets like Aqua Mira or Pure Aqua.
One more thing, yes, REI has a very generous return policy, but treating it like a free rental shop doesn't sit well with me. Encouraging people to do that will eventually lead to the end of that policy.
Don't get me started, you know how I get.