Suggestion on source for small quantities of the "meals"

[cythaenopsis]

I'm not on target to become a prolific tomato grower because I don't really have the space to become one. So, buying large bags of kelp meal, bone meal, crab meal, etc., to mix up for potting just doesn't make sense. In my casual shopping around, I've not yet found any reasonably priced mixes for these meals in smaller quantities. In preparation for planting next season, I'd like to get some ideas of a good economical way to achieve a really good potting mix and fertilizer combination that will give my growing an excellent boost.

Anybody have some suggestions? Thanks!