Nice collection of fertilizers and amendments, out of the ones you still need to get i would prioritize worm casting and myco, they are really the staples of indoor organic. You could even invest into your own bokashi/worm farm since youve got the outdoor space. Its not that expensive and you basicly have an infinite supply of either bokashi or vermicompost or just regular compost. Nothing beats homemade expecially when it comes to price. Another cheap diy amendment you could try are fermented plant/fruit extracts, they are a great tonic/microfertilizer especially if money is tight, just plant materials, LABs, sugar and water. Also do you use covercrop?