Upon turn-in, you will receive 20 tickets which you can spend on 3 different Darkmoon Prizes, containers that will give random items.
1. Buy all cheap Dense Stones you can find in the Auction House
2. Turn them into Dense Grinding Stones. Requires 250 Blacksmithing
3. Visit Darkmoon Faire when it arrives and turn in all your Dense Grinding Stones
Now you have to decide what prizes to spend your tickets on. Every prize can hold valuable items, especially profession recipes. Some of them are worth even 15,000 gold if they are hard to obtain, like the Plans: Radiant Belt Most of them don't contain anything valuable at all however, so it's a risk, but a cheap risk!
Minor Darkmoon Prize
Contains level <-20 items.
Lesser Darkmoon Prize
Contains level <-45 items
Greater Darkmoon Prize
Contains level <- 55 items
Remember, if you obtain a recipe and you don't know how valuable it is, ask me. It's not wise to list something for 50g when it might be worth 10,000g instead!