Is $775.00 plus shipping for the 10hp Hitachi too much?
VFD are commodities these days. Prices can change in a single hour of a single day.
I'd check Wolf Automation, Drives Direct, Drives Warehouse, and whomever else you can find for pricing.. and have USUALLY found meself actually buying from Galco, especially when they have a promo or last-year's model on closeout price.
Otherwise, my 10 HP RPC cost about a hundred bucks less, using all new parts (Weg motor, Phase-Craft starter/control).
My NEWER Phase-Perfect 10 HP was over 4 grand, the used one less than half that.
I STRONGLY recommend against used VFD!!!
There were once a tribe of virtual dreadnoughts built by old-line makers with great caution and deep, deep reserves. If not long-gone, even those are well past their safe capacitor bank life by now.
Newer VFD are treated more as the "consumables" they actually are, so major-maker, "fresh" production, reputable dealer, and decent warranty all matter.
Ex:
$800, eight year life = $100/year for a VFD.
$700, 35 year life = $20/year for the RPC.
buuut... the RPC will have wasted more paid-for 'lectricity than the VFD -roughy 10% vs 5%, so..
Your budget. Your call.