i agree with big v about not spending $25 on a bag of soil but im not a big fan of MG myself. thats why i came up with my own soil mix, to cut cost but not quality. i can make a 1 cubic foot bag of my soil mix for about $ 6- $ 11 a bag with the majority of the costs coming from the worm castings in the mix. if you used mushroom or regular compost in its place it would be on the cheaper end of this range and thats a soil with ingredients like feather meal, poultry manure, cocoa meal, bone meal, alfalfa meal, greensand, azomite, mycorrhizae fungi, dolomite lime, beneficial bacteria, and enhanced with microbes from the fertilizer mix. for the price its hard to beat unless you live somewhere you can get roots organics soil for cheap but thats not many places. and aside from that your not gonna get a balanced mix of ingredients like that in MG. if you get a chance check out the thread. peace