The best way is just call and be nice. They will ship the parts even if it's your first order as long as it's not to much money. When the parts and invoice comes in, mail the check/money order pronto. If he does want you to pay first on your initial order just send it in. No problem. After that you are in like Flynn.
I always call. Yes he may be a little grumpy sometimes but others he is very entertaining and he may suggest a better part or solution. After you get the hang of his system it is actually much easier and it keeps the prices low. Easy ordering and low prices, can't beat that!!