Don't rent tuxedos! We bought DH a beautiful suit for about $20 more than tux rental and he was certainly able to get more than one use out of it.
We also cooked our own rehearsal dinner meal. We prepared a ham, baked beans, potato salad, green salad, mac n cheese, and rolls. Desserts served were a store bought cake, a couple of pies, and cookies. I think we figured that it cost us about $4 per person. We had been quoted $15 per person to have it catered.
We printed our own invitations--unusual at the time. And our thank you notes were bought at a garage sale (leftover graduation thank you notes).