Ok I found an invite I thought was pretty on etsy.
http://www.etsy.com/listing/8191514...ion?category=weddings.paper-goods.invitations. I would buy card stock and look for lace and ribbons at the fabric store, Maybe scraps or even scrap book paper that had a similar patterns. With a good printer you can print your own up and decorate these. So for these particular ones I would print it up, then I would carefully cover all but the width of my lace and use spray on adhesive and attach the lace. A touch of ribbon.. and I have it for MUCH much less. I have done similar for birthday. I can't find my theme or I do find the funky odd theme I was looking for but its wicked expensive. I just copy the look. i am not super crafty or imaginative myself really. I see things I like and I copy them or use them as a pattern and make it myself. Its pretty easy.
Ok so
http://www.etsy.com/listing/7380124...ard?category=weddings.paper-goods.invitations. This is a bit harder but find a nice card stock and a clear stock from the scrap booking isle. A glue gun, bead pearls and some ribbon and you are so there. They even sell the envelopes.
http://www.etsy.com/listing/1065707...let?category=weddings.paper-goods.invitations scrap book supplies, card stock, envelopes and glue.
I saw a drape I wanted to wear for my wedding and went to the fabric store with grammy and whipped up a copy in no time. I do the same thing with Christmas ornaments and cute stuff for the kids. I am cheap which I think drives my creativity lol.
Might also check out sites like shutterfly for photo invites. These can be super cute and not very expensive either. Nice momento for those coming too.