If you pay with PayPal or your credit card you shouldn't have a problem getting your money back if things don't follow through.
If it gives you some peace of mind, you can always shoot Allensfasteners a call or an email at 1.909.223.8347 or allensfasteners@yahoo.com.
With the way the contact info is given, I would guess that it's a guy running it from at home (PO box for address, yahoo email, cell number, etc.).