So, not counting your time to prep for smoke, transferring to the
dehydrator, grinding, etc, your cost @ (just guessing) $0.80/lb comes out at roughly $2.75, including electricity, to produce your 1 cup of smoked, dried, ground onion. Seems like a lot of work, but at least you have a workable process and the resources to make it happen again, if need be.
Were you considering smoking the dried, chopped onion sold in plastic containers? Just for giggles, I know the large plastic jugs cost around $12 at big-box outlets, but not sure what the volume of ground would be. OK, just grabbed ours for a peek: 3.12lbs dried & chopped...probably ~80% (maybe closer to 85%) loss of weight from drying, so for the sake of simplicity, (from 1/5 remaining weight) 5 x 3.12 = 15.6lbs chopped onion before drying...just a guestimate. By comparison $0.80 x 15.6lbs = $12.48 for those same onions, before chopping & drying. I'd have never guessed this one, but you're money ahead buying chopped/dried, then smoking those on mesh trays and grinding it all up. Not to mention, no peeling or knife-work for chopping, no drying...damned if I would have guessed this one!!! And, to top it all off, yield of finished ground onion would be roughly 5 cups, with a bit to spare...quite a batch for the pantry stash.
Check my math if you want, but I think It's correct.
Eric