Each photo will cost you $1.49 to have printed, and postage is free in the US (0.99 cent everywhere else).
The only drawbacks are that your account must be publicly viewable (something the company says it is working on) and that it is not currently possible to track your postcards’ delivery status.
There are a number of other Instagram printing services available, like the popular Printstagram, but Repostage takes a different approach from competitors by just using a hashtag to request a print. The quality being offered by Repostage is good as well with each image being printed on 110lb card using archival ink.
Image credit: Repostage/Facebook