I love the use of craft paper and the bold and colorful design used on the outside of the very simply printed invitation. This actually is something I can see doing myself with either fun paper from the art store or with fabric.
These invites from Printable Press are so delightful... in fact, so much of their stuff is, but there isn't one that quite grabs me just right. However, the great thing about these is that you can order one of their designs customized to your information, and then print it at home or at a local printer. The design costs $70 and when I looked up printing prices, it looks to be about $30. So, this is definitely an affordable option for very cool cards. And, it has a nice mix of designer influenced style with DIY practicality which I like.
Then, there are all of the lovely designs at Wedding Paper Divas:
These are customizable to a point with colors and the wording you want, and they come fully printed for an affordable price. I think most of these are about $1.60- $1.80 per card, which, to be honest is probably cheaper than I'd get away with if I did them myself what with the nice paper and factoring my time, etc. If I went with one of these (we're leaning toward the top one) we could also do something to make it more personal such as playing with the wording, or the fonts, or adding my own printed and stamped response cards or a fabric wrapper around the invites. That is probably what we'll do, but in the mean time, I'm looking around for other fun options.