We did some beautiful save the dates using Vistaprint that I loved!
I found www.paperandmore.com, a website selling DIY parts of invitations, specifically weighted linen cardstock, belly bands, monogrammed squares, and envelopes. We were able to order samples of everything and then do practice runs with the samples.
We came up with our own design on Microsoft word (after looking at and rejecting a bunch of templates online) and changed it to a jpeg for printing. We used generic wording with a few tweaks. I used a laser jet printer to print the invitations and set it to the setting for heavy cardstock. Then the fiance and I compromised on a little less glitter in exchange for metallic envelopes and belly bands (his idea).
We did have to use envelope labels as the envelopes were too dark to write on. I still wanted more glitter and the fiance wanted something similar to a wax seal, so we found these glitter envelope seals for CHEAP at Michaels. Then the fiance made a custom stamp with our logo (a little blood, a lot of sweat, a few tears) and voila!
I took them to the post office to be weighed. We had included reply envelopes in some of the invites for older relatives, but had everyone else rsvp on the website. The reply envelopes required additional payment but the other ones only warranted the 0.70 stamp due to their size. I even found matching blue butterfly stamps at the post office. Score!
I've been told they are very classy with just the right amount of glitter.