Question" I have a 1974 silver dollar that looks new with an S on it. Someone turned it into a store for a purchase. Is it worth something? Also a 2007 gold plated quarter.
The answer to both your questions is - face value.
1974 S (S is the mint mark - San Francisco Mint) Eisenhower silver dollars that are in mint state (uncirculated) are worth up to about $10. Yours is obviously circulated since you state that it was used for a purchase at a store.
As to your 2007 gold plated quarter - it is a novelty item and did not come from the mint with gold coating. The gold coating was probably added by a private company and is so thin that it does not even increase the intrinsic value (i.e. the value of the precious metal in a coin).
It could possibly be worth a couple of dollars to someone who enjoys collecting these gold plated quarters. Serious coin collectors only want coins that have not been altered in any way. They want them just the way they came from the mint.