Your local feed store may be quite a bit cheaper than a big box store like tractor supply or atwoods. At the time that TSC is selling 50 lb for $22, I can get feed produced in the region that is very good rabbit feed for $15 for 50 lb (which is probably going to go up but then so is everyone else's). So check out your local feed stores.
You can cut costs on minerals by buying the big mineral blocks for horses that are about $5 and break them up with a hammer. Once they're broken up you can drill a hole through each piece and wire it to the cage just like those expensive little round ones they sell for rabbits. Plus it looks like a designer salt lick LOL
