I moved to anew place where the soil is mostly sand. I decided for the moment being to garden in containers. I am up-cycling an old steel file cabinet : 5 drawers h 12 x w 19 x L 41 i, on cinder blocks. and the body of the cabinet is H 19 i x w 41 i x L 64 i, on bricks.
I estimate that to fill this with store bought potting soil would cost some 600.-- Dollars or so - which makes those tomatoes VERY expensive and the whole project not viable.

I can get as much free compost as a want (made from leaves and wood clippings, only) from my county's Dept. of Solid Waste Management.

Does anybody have a recipe for homemade "potting soil", or can point me to a recipe, so I can fill those steel beds at a reasonable price?

I normally garden organically and while I am sure the County compost is not organic, it will have to do. Plus, if any possible, I would prefer not to use peat moss for environmental reasons, if an alternative can be found.

Thanks for any suggestions

I've made my own potting soils and native soil amendments for decades. It's a very simple recipe but seems to work well. Composted cow manure is the main ingredient. You'll be using compost from another source, but I would think the proportions would remain the same. I use 2 parts composted cow manure (something like Black Kow), 1 part cypress mulch, and 1 part super coarse/chunky perlite. For every 5 gal of this mixture, I throw in a small handful of a balanced, slow release fertilizer (something like Osmocote). I purchase the mulch in 2 cf bags (cheap) and the perlite in 4 cf bags (more expensive).