Sign-up for a vendor on mywedding.com requires a year long commitment.
I went with the high-level, featured spot since it was still cheaper than it's competitors, and I can see why!
I received ZERO business from this site. I didn't even have many clicks onto my vendor page within the site. If you're looking to advertise as a wedding vendor, use The Knot or WeddingWire.
MyWedding.com is basically the same service as The Knot or WeddingWire. It's less expensive but I received absolutely zero return on investment from this site.