Please offer PayPal as a payment option. I have been using it for years with no issue. For those of us who choose not to have credit cards, there should be a simple way to pay for materials. I have had to mail checks in and wait — what a downer. When a good sale or something comes along, it would be nice to just jump on the bandwagon and start reading, etc. (I'm trying to give you more money — won't you help me?)
With all the resources you have in your catalogue, and how spendy some of them are, it is difficult to see the business sense in eschewing ANY payment method. I write this as a business owner myself.
Just my two shekel's worth. But seriously, get PayPal. Please.