I think a lot them are really just the same main company but they have different websites. I used envelopes.com for my custom printing. The envelopes and printing themselves were GORGEOUS!!!! Everyone loved them!!!! I paid a little over $150 for 40 #10 and A1 envelopes with custom printing. However, keep in mind several things. It can get expensive and it can be take a while for them to go to print and ship to you.
We ordered #10 quartz metallic envelopes for our boarding passes and A1 cards in the same color for our RSVPs. I didn't include an image in mine. I just wanted the addressing to match font we used previously. If you have multiple colors it will increase the cost. I used 3. If you want recipient and return address printed that will increase the cost. We just did recipient and did labels for the return address on the #10. On the A1 we did all the same recipient but with the same colors.
You simply upload your design and your addresses. They will get back to you (usually the next day or two) and let you know if there are any issues. We had to change our design a few times because of postal regulations for the zip code. Once you approve the proofs they send you back it goes to printing.
Because of when my proof was approved, mine didn't go to print until the following week. So if you need rush printing make sure you request it. (That wasn't clear to me.) And if you need it shipped in more than a week you also have to pay for rush shipping. HTH
Edited by puravida2015, 04 December 2014 - 08:06 AM.