My friends and I have ordered dozens of times from PBR and don't mind sending checks/money orders. This helps to keep costs down and prices low. I'm all for keeping the prices down. Lower prices means I can afford to buy more parts.
Sure, you can buy parts from Marco Specialties, but you'll pay double the price for the same parts.
My buddy Welby has literally purchased thousands of dollars of parts from PBR over the past 5 years.