Good place to mock auction

Looking to get into an auction league for the first time and wanted to do some mocks to practice. Any recommendations for the best place?

My paid mock league is on Yahoo so I tend to mock there so I have a decent idea of average price of players. So if you know which platform Is recommend using that one. Yahoos not too bad to mock on though. Definitely better to mock with other people though. The computer makes very dumb, predictable bids.