Hey Russ--
Congrats on your site.
I do want to add that PayPal doesn't allow you to pass on a fee to the buyers. While this is common on forums, and among those who maintain that they are not dealers, I do believe you could quickly find yourself banned from using PayPal.
First, I wouldn't put PayPal on your front page. I'd suggest you create a "payment" terms page. I'd also suggest you offer a discount for cash transfers, money orders, etc.
Second, PayPal has canceled its services with some dealers -- notably Bill Shea of The Ruptured Duck. So again, I'd suggest you downplay that PayPal is a means of payment on the front page.
Third, PayPal cannot be used for the sale or other transaction of firearms. This is also against the user agreement. I believe, if I've read the user agreement correctly that even gun parts (but not holsters, cases, etc.) are not allowed.
I say this as a collector, but I am also a journalist and I cover e-commerce. PayPal has issued warnings to seller of collectibles beyond militaria (baseball cards, antiques, etc.) that adding 4% fees is against the user agreement.
I should also note that these added fees for credit cards, which are higher than bank transfer are there because ALL credit card companies charge vendors those same fees. So any store for example pays fees, and the credit card companies generally don't allow said fees to be passed on either.
Just my two cents.
PS