Buying a house from the sheriff sale

[Precious Smith]

Hello I’m new to this so please feel free to educate me if I sound uneducated. So I have a friend who “claims” to have bought a house from the sheriff sale for almost $4,000. I wanted to do the same but as I look up information on the sale it tells me I have to put up 10% of the price of the home then come back in a week to pay off the rest. So my question is if the home is worth $40,000 then 10% would be $4000 which means I still have to pay the $39,600? Right? Or how does that work? Please help me