Cash For Gold are stores seen in the Season Sixteen episode, "Cash For Gold". These stores bought used jewelry and resold them at higher prices.
Stan's Grandpa Marsh gives him a bolo tie he bought off the J&G Shopping Network, thinking it was a replica of King Henry V's tie. After Cartman makes insulting remarks about it at the bus stop, Stan tells the others it is supposedly worth $6000.
Kyle suggests they try various Cash For Gold stores opening in town. Every store offers very little for the tie. Eventually, they end up at Taco Bell, which also buys gold, and the cashier only offers one burrito for it. Stan decides to keep the bolo tie but Cartman begins his new business venture in the Cash For Gold scam.
How Cash for Gold works
The stores advertise they buy old jewelry or anything made with gold including; coins, teeth fillings, trophies, medals, and other items people tend to discard. These items are sold to another buyer, who smelts the gold back into a pliable material that is sent to India.
Once there, it is turned back into jewelry and sent to the J&G Shopping Network, where it is sold for a high markup. This jewelry is given as gifts to their family, who then resell it back to the Cash For Gold stores, thus perpetuating the cycle.
Every store is adorned with colorful advertising on the windows. They tend to have obnoxious sign flippers outside to attract attention.