Ok, this is to keep the game running, because you cant use this idea unles the game is running. Paying for servers and stuff.
Ok, so you wreck the economy of the game and make money hard to come buy, like quests give about 10 of the currency, monsters drop about 1. Players will sell super strong weapons for 100-1k of the currency. Then, on your website, for every $10.00 a member donates, they get 50k. If they donate HUGE amounts, you give them super rare items or super strong ones. Sounds good to me.