I just started playing this game. It’s awesome. On what item should I spend my quest points? I have about 300 points. Thanks

Get whatever you want! Personally I usually go for books first.

If you wanted something to sell, you can offer your points on the Advertising forum. You can do some checking in other boards for how much quest points (QP) go for. For example, if the going rate is 20k/pt, you can list your points, and someone will list the item(s) they want from the shop. If the total was 15 QP, they would pay you 15*20k = 300k for the item c:

I made that number up for a sample though, I haven't checked out QP pricing in a while.

The stickers sell pretty well