Ground scores are my specialty... My biggest score in cash was $200, four $50 bills folded up nicely just laying on the ground. Just the other day I found a $20 bill on the floor while in the grocery store, and two silver dimes in the reject bin of the CoinStar.
ALWAYS check the reject bin on those; if people overload them, they frequently forget to check it, and I've scooped an entire handful of coins from them, many times. Then I check them for the older 1964 and older dimes and quarters, as those are made of silver. The must weigh more, as they always end up in the reject bin.
The coolest thing I ever got in trade was about 20 years ago... I had helped to renovate a couple of homes for this guy, former rental properties that were trashed, and he was going through a divorce and was trying to sell the places, so he was strapped for cash, but was a coin collector and had a bunch of coins. And he offered to pay me in gold... A one-ounce gold Krugerrand, and 8 European gold coins that totaled another couple of ounces. Back then gold was a little over $400 an ounce, and since he owed me $1500 and he gave me $300 in cash, I took the gold coins for the balance. Later that summer I worked for him again, and we came up with the same basic deal, this time, 12 European coins, totaling about 3 ounces of gold, plus a few hundred bucks in cash for the same amount of work.
I never did sell the coins, I only verified them with a coin shop as being legit, and I put them away in a safety deposit box, along with a bunch of silver coins I had accumulated over the years. Today, just over 20 years later, those six ounces of gold coins are worth close to $14,000. SO glad I took the guy up on that offer all those years ago, as if I had insisted on cash I would have just burned through it.