I think the prices are pretty cheap and people shouldn't gripe about how high the are, they're exactly the same as the monetary prices. (Selling art for 20 is the same as selling it for $0.16, which is pretty much robbery. ) Keeping the points the same as the $$ prices encourages people to pay with money. Frankly, points don't pay bills. They're useless anywhere else expect dA. So, I don't think you should lower your prices, unless you do some sort of sale or special offer.