Yahoo now offers a Free-agent acquisition budget. I've never used it, but how it should work is everyone gets a set amount of waiver money at the start of the season. Anytime a player is put on waivers (new add, or dropped), instead of putting in a claim, you put in a bid. Bids are blind, the highest bidder gets the player and pays that much from the waiver account. Run out of waiver $$ and I reckon you can only pick up free agents.
I've always liked the idea - everyone has a shot at every player to come through waivers. Or we can do the good old-fashioned waiver priority. Starts in reverse order of the draft, when you claim a player you move to the back of the line.