The price for Morimoto ballasts is $115 for a set, I don't think that's expensive at all considering what your getting.
Morimoto aftermarket ballasts are extremely reliable and warrantied as such. See theretrofitsource.com
They are completely waterproof (not just potted) and their fit and function is comparable to OEM.
Personally, I think they are the closest to OEM that you can currently get. The three top hid retrofit shops in NY and the two top ones around here, use only Morimoto or OEM ballasts, that says something.
I've gone the cheap Chinese made ballast route, threw them out within an hour of install....
The Morimotos I replaced them with have about 3 years of solid reliable start ups on them.
I'd suggest checking out the site above and looking at the specs of the ballasts, their quite impressive.
So no, I don't think price is the problem at all. At $115 the ballasts are by far the cheapest part in my retrofit.