There is no minimum of deposit. But, we highly recommend to make the biggest deposit you can. When the buyer is supplying its Auctionity account to take part in auctions, it is recommended to add more funds in one setting rather than adding several small amounts in several settings. Indeed, the supply comes from the blockchain Ethereum Live, so gas costs are applicable for each action performed. The gas costs are the same regardless of the amount transferred, so it is better to add a large amount at once rather than several small amounts. In addition, the transaction validation time on the Ethereum blockchain is about 2 minutes, so it is wise to have enough funds available to be sure to win an auction.