I have too many stones of various sorts...so let's go a slightly different route.
Based on the recommendations of a couple of highly esteemed members here,
@HeavyHanded and
@David Martin, I'd recommend the following combination. You can move on from there as you progress if need be:
Norton IB8 Double Sided Stone: 100 / 320 grits, $22 online
Ultra Sharp Diamond Double Sided Plate: 400 / 1000 grits, $53 online
Optional:
Powertec Stone Holder, $15 online
That's $90 plus tax on amazon, all in.
(I can't provide the links or I would be breaking the rules I'm supposed to enforce here. Prices may be equal or better elsewhere, but they seem reasonable to me.)
If you need something finer, you can go with a finer diamond option or ceramic with the remaining balance of your funds. Just depends on what your desired finish is.