For the credit economy showing the stability/price for credits. Obviously it'd be a ton of work, but I assume you'd be able to considering you've made so many custom plugins on here. Also add a Credit to USD/EURO/POUND/etc conversion chart.
I don't think it's allowed to sell credits for USD, so it'd be useles.s
Well in the rules it says you cannot sell credits for money. But if you'd want to sell something for credits, an item, virtual etc then you could.