So, I was right--I've been looking up letterpress pricing and most places run between $1100 and $1300 for the quantity that we would need. YIKES. And that's just invites, reply cards, and envelopes. No ribbons, inner envelopes, or other embellishments.
That Etsy vendor is looking more reasonable, although honestly, $700 still seems crazy to me.
I did find one letterpress vendor that has done letterpress printing since 1946 (!) that was more reasonable, mainly because they do it with polymer plates instead of lead type, so it's a slightly different process than traditional letterpress. Their stuff still looks beautiful though, for example:
The absolute cheapest (one color of ink, completely blank envelopes) would be $400. Also, it would mean we would have to go with white or cream stock, which I didn't initially want to do--I was thinking orange stock with black ink.
Two ink colors, blank envelopes, would be $630. It's worth considering, I suppose. Also, they are local to us, so we could even go pick them up if we're allowed--no shipping costs!
As I was looking I found these great letterpress Halloween cards from local vendor "Hello Lucky!". Mmmletterpress. The second is a great way to make the most of one ink color, I thought.