Economical grain free dry foods

So, it looks like I'm going to be helping where I can, in managing local feral colonies. One big need is food! One mom/son family has a feral colony of 14 cats that have been TNR'ed. The mom has terminal cancer and the son works long hours. They're definitely in need of assistance!

I will likely donate canned Friskies to them when I can. But that only goes so far among so many cats! So I'm looking for economical grain free dry foods. Preferably about $2 per pound. I was thinking maybe Taste of the Wild or Whole Earth Farms. Any other choices for good foods to feed to a feral colony?

4Health grain-free (says it's for indoor cats, but I don't know how it's different). Costco has a grain-free cat food but it's fish based.

Do they need grain-free? I like regular 4Health or Kirkland (Costco brand) for ferals.

Thanks for the suggestions! That's right, I forgot about 4Health. I shop at Tractor Supply a lot!

I suppose that the ferals will appreciate any food that we can give them, even if it's not grain free.   

I kind of figure that the other starches in grain-free foods aren't any better than grains :dk:. Especially if they use potatoes. . .a lot of cats don't do well with potatoes. A grain-free canned food, if the grains aren't replaced by other starches, is great, but a dry food needs a starch and I'd rather not pay extra for non-grain starch sources. Unless the cat is sensitive to grain of course.

I often order from Chewy and Amazon.  I recently discovered Warehouse deals for cat food on Amazon where food starts out discounted but the price goes up as time passes. I  compare with Chewy before buying.

Karen