It has become apparent to me that the most stressful part of the wedding (at least in my opinion) is the invitations. My mother and my future mother-in-law have both been great help with this task, but I still tend to get a little overwhelmed when dealing with the invitations.
First, I printed my invitations myself! I caught a sale at Hobby Lobby, so all my invitations were 50% off. Printing them was quite easy. My invitations include a basic 5 1/2 x 8 inch invitation card, a 3 1/2 x 5 inch RSVP card, and also a small card with directions to the venue. Even though I included so much in each envelope, transferring all the addresses to the envelopes was the stressful part of this task.
I recommend getting some standard size address labels from Staples. I tried to use some that were smaller than average, and I could never seem to get the text to line up with the label. All this stress could have been relieved had I simply forgone the "pretty" labels, and bought the standard white address labels at Staples. Take my advice - the easier, the better!