I just finished printing out my invitations and response cards at home! I used cardstock from a company called LCI Paper (
www.lcipaper.com). I just wanted to let everyone know about this website since I don't often see it mentioned here often. They very affordable and quick to send everything out.
I'm having a subtle beach theme wedding, and LCI paper has 100 lb. cardstock with pearlized shells around the border. I've seen these invites elsewhere, but on other sites, they were only sold printed for about $200 for 75 invites and response cards.
I ended up buying the cardstock for 100 invites and response cards with single envelopes for $114 (including shipping). I used my home inkjet printer to print everything out, and they look great!
I honestly thought printing my invitations at home was going to be a disaster, but it was super easy. It's definitely a great option for those of us on a budget!