My suspicion right off the bat is that, like the person above said, that Berry's bullets are plated, and Hornady's are jacketed. And jacketed bullets cost more than plated.
But also, as much as lots of reloaders like Berry's, in the grand scheme of things, Berry's is nobody next to Hornady.
And finally, for the advice you didn't ask for
, you should look into coated lead bullets from someone like Acme Bullets, SNS Casting, etc.. They are cheaper than plated, and in my experience, you always get at least equal accuracy to plated, and often better. AND you use a little less powder for the same velocity. It's a win win win.