Hollybird, do you know about letting the eggs settle before you put them in the bator? They can get little air bubbles from being shook up, and still be ok, but you have to let the rest, small end down, undisturbed for 24-48 hors before you start the incubation, That give time for the bubbles to be reabsorbed, and everything back where it belongs. Some eggs of course, won't develop anyway, and some are too badly damaged, but that gives them a better chance.
I know how you feel, I have a $21 Dorking chick, the lone hatcher out of 15. The seller has kindly offered to replace them for shipping only, which I thought was very kind of her, considering it wasn't her fault. The package had been pretty roughly handled, I could tell. I'm waiting until Sept. or Oct., partly because of weather, partly due to family things going on. (I may need to be available to go out of town.)