So basically how it will work, there are special/unique ranks and untradeable items that you get for giving money to a staff member to take out of the economy so it will keep the economy more stable and you get a reward for doing so, the last server I played had this too and the economy was very stable but due to owner's personal issues the server was stopped.
The ranks increase the more you donate to be removed and with each rank you get new/unique items like armour dyes,new cosmetic or skilling armour and other custom items that are untradeable or you could make it a token system so you can trade 1b coins for 1m tokens or whatever rates you would like but the idea is to make it quite expensive for items people want and can only get from this system.
items to possibly add to the store:
Nex items (Torva, Virtus, Pernix) / New armour sets
Armour/Weapon Dyes
New Skilling items (armours/skilling tools)
New dyes for cosmetic items (Phats, Santa's, Sleds etc )
or any other items you want in the shop.
New weapons (katana or other custom weapons etc)
I only make this suggestion as a lot of people are talking about a economy reset and that will be the last thing anyone who plays the server wants to happen.