I only ship flat things in envelopes first class (art,work, prints, or small padded envelops with badges), so I was likely looking for the large envelope option or any envelope. I'm pretty sure paypal didn't have the option to print postage for envelopes either first class, though I can check again. From what I saw the only way to print first class postage was through these other sites. I went with stamps.com becuase they gave a free trial run of a month.