I got this a bit late (and then was even more delayed posting this). I had an issue with my account and had to cancel and resubscribe and in the process missed the deadline for May buuuut they still had mine from my old account set aside. So they let me pay for it anyway (and even let me add the new envelopes to it) because they’re awesome.
If you want to try out La Papierre this package is $16 shipped in the US. You get four sheets each of six designs plus six matching envelopes (one in each design). There are several other packages you can also choose from that include more or less sheets of each design. You can also choose to get more envelopes or none at all.
You should also check out The League of Extraordinary Penpals if you are in search of new ways to use your stationery.