Scrounging is kind of an aftermath skill, I guess.
Yet, if you don't clear tens of thousands of "extra income" after meeting your needs, scrounging is a skill that will serve you well. In the 80s, I really embraced resaling and pawnshopping. Always great fun and an adventure. Got nice suits for work. Great deals on firearms at pawnshops. Lots of cookware, cheap books/records, outdoor gear, and anything else I could find.
Resaling would have horrified me as kid, but when I first went to the old Purple Heart Thrift Store and found lots of "treasures" for cheap, I was hooked. I visited every thriftstore I could find, and had a regular route. Certain Goodwill or Salvation Army stores would have more of certain items, I noted. Regular visits enabled me to hit the motherload on occasion.
As the American Middle-Class has been ruined by outsourcing jobs overseas, payments to industry to relocate abroad by our Gov't, and union-busting industrial decimation; more and more formerly middle-class folk are resaling. If you haven't got the habit yet, you ought to. Nothing wrong with buying Nearly New stuff at a fraction of regular price. Even better is getting gear on Discount Day...
Pawnshops are especially productive for tools and gear. Always pay cash at a pawnshop. Always offer 1/3 less than merchandise is priced, and tell them you're paying cash. If you pawnbroker won't deal on used goods, find a pawnshop that will. NEVER BUY UNLESS YOU GET A DISCOUNT...
Considering a "Food Storage Plan"???
Before you shell out thousands for not very nutritious freeze-dried meals in a can or pouch, pay a visit to a few of your local healthfood stores. Very easy to store whole grains in new, 5 gal paint buckets with gasket lids. Use Dry Ice you buy at the grocer's to preserve your food. In 2009, we opened a bucket of organic short-grained Brown Rice bought & put up at home in 1995. The rice was Perfect!
If you are going to eat, may as well eat food that is High In Nutrition and Builds Your Immune System. None of the foodstorage junk in a can will do this; you have to cook from scratch and use quality ingredients.
A Survivalist needs lots of tools for Food Processing and Cooking. Buy them at your resale shop. An old pressure cooker will work as well as a new one; just buy a new gasket set at local real-hardware store or order online for $10. Quality cookware, knives of all sorts and gadgets are all at the Resale very cheap. Got a nice 10" chef's knife, made in Japan for Fifty Cents recently. Thrilled because it really takes a nice edge and carves very finely. Better than the $30 Chicago Cutlery 8" knives we already owned when comes to fine slicing.
Got plenty money? Suit yourself, but as for me, I'll take $5 Levis in new condition, $3 moleskin shirts, $1 T-shirts and socks and even decent shoes or boots if can find them. Rarely buy anything at retail if can get it at a resale or pawnshop.
Doing home improvements? Habitat Re usually has a resale shop. They get donations and resell to renovators/builders. Always a fun visit.
Some people love garage-saling. Never had the time.
Craigslist.com is also worth perusing for gear you're looking for cheap, or maybe even free!
The more you conserve your assets, the more you have to work with.
Buy a Nordstroms dress shirt for $4 or $75. Not like you will know there's a difference after its been laundered...
On-line forums are also great places to shop. Lots of these allow WTB want-to-buy listings. Gun forums are quite active for almost everything. Gunbroker.com is a good resource for accessories and handloading/optic stuff. Shop the used listings, and look for individual sellers; guys with hundreds of listings don't usually deal...
Ebay is still out there. Might find some gear priced low and use a bidsniper to win the auction if you have the patience.
Lots of ways to scrounge stuff up that you probably can use and save your serious funds for those items absolutely must have... All the best!