If you can get a deal on mushrooms, just regular plain white mushrooms. . .
Slice them thin and dry them--they smell wonderful (or at least they smell wonderful to me!), rehydrate quickly and are pretty handy to have around for sauces and such.
Just yesterday I watched a video making rice flour in a Vitamix and turning it into crackers in their dehydrator. You might do a search on raw foods & dehydrator.
I've been doing this a lot. The two I do most now are Green onions and Leeks but you can do anything. Powdered chives are the "secret ingredient" You can use it for SO much. On your morning eggs; make a nice dip; add to soup - or just about anything. I like it on my brie... Add it to some of your other seasonings for some extra good flavor. We even put it on popcorn.
Nice thing about the leeks is you get to use the greens that most of us normally discard.
In this photo are some of my recents. For you cilantro-phobes, my apologies. But the unmarked
include powdered smoked garlic and a spicey jalapeno/onion/carrot mix. You'll also notice Budda's Hand which has a great fruity fragrance.
After drying I use a kitchenaid coffee grinder (now dedicated to spices) which works nicely all the way to a fine powder if I desire. The white on the Leeks jars is wax paper which I use to keep them fresh until they get opened.
I would not recommend this. I did it as an experiment but it actually came out decently. This is Cheddar cheese which I shredded thin then dehydrated then powdered. It took forever and not worth the effort IMHO but I just wanted to try it...