Cheap HP Pro Mix soil mix?

Title explains it all, needing a cheap mix from hp pro mix for 8 cubic feet, iv'e been hydro all my life and am now merging to soil. Any suggestions? kinda needing this asap due to sprouted seeds, would also wish its not to hot for seedlings but still enough ferts in the soil to grow a decent amount to mix with a worm tea without burning.

I may get crucified for it but I go into solo cups with MG seed starter with about 25% added perlite and baggie over the top. Then I remove the baggie and let then grow a while before repotting into larger (3gal) with final soil mix. For that I use about 30% peat moss (close to promix I think but haven't used promix), 25% cheap no nute potting soil, and the rest perlite and vermiculite with 2T/gal lime and some casings. Plants seems really happy.