I'm adding funds to my account by PayPal. For unknown reason you process such transfers manually which takes a couple of days. It may happen that my balance is too low, I need to add a snipe but cannot because of lack of funds, and there is not enough time to send you more funds. What I would suggest is to email me every time my balance is critical low. Here is how to determine if it's low. Imagine I have $10.20 in account and I scheduled two auctions with my max bids over $500 each. This means that, if I win both, the remaining balance will be only $0.20, less than the smallest fee. It's what I mean by critical low balance because I won't be able to add any more snipes. Even better, let the user set the minimum projected balance (what would remain if he wins all scheduled auctions at his max prices) is below the user-defined value. Some credit card companies like Chase do this, it's a very useful tool. You could send the user a PayPal invoice with predefined fields on such events to simplify payment.
