OK, I will step into this minefield. I am what some would call an extreme couponer. I would call it coupon arbitrage. Let me tell you a bit about what I do.
1) I don't clip coupons or print them out. I buy them from ebay in sets of 20 for about $2.00 shipped.
2) My store (I only do this at one store - see below for why) doubles cuopons up to 99 cents so a 75 cent coupon = $1.50
3) My store is 6 miles from home and on the way from work.
4) What to do with 200 bottles of mustard (never did that)? Sell at a garage sale. Small/light items- sell on ebay.
5) My store, (Martin's/Giant in MD/PA) has gas points. The normal gas points is 1 point per $ spent. every 100 gas points gives you 10 cents off per gallon up to 30 gallons (tip - use gas cans to get all 30). So, 100 points = $3.00 But, the GREAT thing is they have bonus gas points for buying a certain # of items. Last week it was buy 7 get 400 gas points. On that list was Gatorade Energy chews for $1 each. So, buying 7 of those for $7 = $12 worth of gas. If you throw them in the garbage on the way out the store you just 'bought' gas for a 42% discount. Now, what I did was buy 70. Cost was $70. I got $120 worth of gas. I don't eat energy chews but others do so what I did was sell them on ebay. After ebay fees and shipping costs, I got $56.44 for the 70 energy chews. So, my net out of pocket cost for $120 worth of gas was $13.56. Let's say that the whole time involved was 2 hours (probably much less as I d my regular shopping there anyway) that means I 'made' $53.22 per hour (after tax) on this transaction. by the way, no actual coupons were used on that deal!
Here is an even better deal that did use coupons. Neutrogena bar soaps. They were on sale for $2.19 and on gas points for buy 3 get 200 points. There were $1 off 1 coupons out there so I bought 60 of them for $6.00. Bought the 60 bars, paid $75.69 out of pocket at the store (so 81.69 with the coupon cost) and got $120 worth of gas. Sold 50 on ebay(kept 10 for the wife) for $91.25 net after fees/shipping so that deal netted me $120 in gas, $9.56 in paypal account and 10 bars of pretty nice soap.
Last deal - GE CFL bulbs. These were on sale for $1 each with buy 10 get 200 gas points. There were $1 off 1 coupons out there. I bought 200 for $20. Then bought the 200 bulbs for $12 (tax only). So, I got 4000 gas points ($120.00) for $32 out of pocket. Sold 180 on ebay (kept 20 for me) for net $122.40. So on that deal I got $120 worth of gas, $90.40 (net) to my paypal account, and 20 CFL's for the house. So, about $240 after tax for2 hours work.
Now these were realy good deals. Not every week is like the above. But, I have been able to have a good little 'side gig' going using a bit of math and the power of the internet to work a bit of coupon arbitrage. Works for me.