Also, should you buy broadheads with replacements or ones you can sharpen on a stone?
Just my opinion, but that depends entirely on how good you are at sharpening. If you're good enough to put a shaving sharp edge on a stick of butter, then buy the resharpenable kind. If you're so bad at sharpening that your very best effort still cuts like a stick of butter, then you're better off with the replaceables.
If you can resharpen your own heads, you'll save a buttload of money in the longrun.