Check to see if your bank offers online banking. If they do, then you can add the seller to your "Payee" list just like you would if you were going to pay your VISA or phone bill online. Once you've added them, you simply tell your bank to cut a check for the correct amount and send it to them. Once you've received your item, you go back in and delete the seller from your Payee list.
I've been doing this for several years, and I've never had a problem. And by doing it this way, you see it on your monthly banking statement so you can keep track of purchases.