A lot of artist sell units through Cdbaby. As far as I know you supply them with a certain amount of units and from there they take a little off the top (you can raise the price by a few dollars) but they handle the shipping and everything so it's a little easier to move products online. That's really the benefit. If you prefer doing everything yourself which quite a few do, you can also set up a paypal account and recieve payments via electronic checks and credit cards. You supply the packaging and do the shipping yourself this way. The oldest way is by mail, they send cash or money order, when you recieve it through mail you continue with the package. This takes awhile so, online merchant accounts or services like Cdbaby can be beneficial.