They will place an order with you and while they are waiting for it to be returned, you will have no problem at all talking to them.  After they get the order back in their hands, however, you will not be able to get the to answer any email or return a telephone call.  My invoice was marked "NET30" and I was told 'we pay on NET90 but if we get paid before then, then we will pay you sooner.'  No email has been responded to and no phone call has been answered since then.  If you enjoy giving away work, especially in a remote county, go ahead.  If you expect to be paid, however, tell them to pound sand.