Woooah, put the wallet away, please
If it turns out the photos don't open on other computers either, it still might be possible to fix things without paying for recovery.
Do all photos taken by the same camera now exhibit the same symptoms?
Did you perhaps use a different CF/SD/xD card for this batch of photos?
If you copy one of the "broken" photos back onto the card and shove that into the same camera, can the camera display the photo correctly?
Given the bulk of the JPG body appears to be present and accounted for, I expect you'll be able to get these photos back.