It sounds like you are doing your draft online anyway, you should consider using http://www.fantasyauctioneer.com
. We have used it the last two years and it has worked out great. It amounts to a little over $2 per owner, it is $29.99. The downside is that you would have to get each owner to register at their site, which take five minutes at most. Then as commissioner you would have to add the keepers. After the auction you would then have to add the players to whatever stat service you use. The upside is a true auction, and the system does a great job of managing the auction for you.
Thanks - Rey