I heard from a friend today that he received an inquiry over the internet from someone who wanted to buy one of his paintings. I hope it was for real, but I did take the time to warn him against a common scam. Perhaps you already know about it, but in case you don't, here's the deal.
There is a scam that targets artists and any one else who markets online. What usually happens is that you receive an e-mail, often in stilted English, that says something like " I have seen you paintings on the line, and I am most serious to buy many.
They often want to send you a cashiers check as they are foreign or moving. They ask to overpay you for one reason or another, often shipping, and you are to deposit the check, send them the paintings and the balance left over from the cashiers check after what ever arrangements you have made. In short you are to take a cashiers check, let it clear and mail them money. What most people don't know is that a bogus check can clear your bank and then be rescinded.
Many artists are so delighted to receive the sale that they comply. What happens next, is the bank contacts you in a week or two to explain that although the cashiers check appeared fine and they have posted it "cleared" to your account, it was a fake and bounced. The check was a fraud. You are out the balance that you sent to the customer and perhaps a painting or two as well.
The easiest way to avoid this is to set up a paypal account and take the payment through that. If the client won't do that, walk away. No matter what the deal is don't do business with anyone in Nigeria. If that seems unfair to you go ahead, but I warned you.