To make basic cheap wedding invitations pop out and be unique when your friends and family open them, here are some ideas on what you can add:
Bind a single rose matching the type your fiancée gave you on your first date
Add some glitz to the invitation by creating a border made up of beads, jewels, or rhinestones
Add a personal touch that will give your guests a little taste of you and your fiancées personalities.. get thinking and get creative.
Make sure you don't do too much when adding a bit of dimension to your invitation packages... you don't want to distract from the actual information inside the envelope.