I found my invitations at Paper Paper in Del Mar. If I remember correctly, they were $15.00 for 10 ( I bought 20). They were also going to charge me $30.00 to print them so I just bought some card stock and cut it into the same tag shape and did a trial on my personal printer. It worked perfectly so since I splurged a bit on the invitations, I saved by printing them myself. I could not find a website for Paper Paper but here are the invitations I got ——> http://www.polkadotdesign.com/catalog/Mara_Mi/MM-MM08670.
Of course I just found these instructions online after the fact, but hopefully it saves you time!