YCH's auction's have quickly moved into the predominant form of art commissions on YCH and :iconryotsuke" (Who's super fucking sexy...btw....*closes eyes*....*Ahem*), has a really nice website for faciilitating Auctions between FA, IB, and Weasly.

https://auction.ryotsuke.ru/#page/becomeSeller

I'd check it out and recommend your favorite artist use it :O