I bought a trash can (20-gallon) for $13, air stone for $2, pump for like $15-20, air line for $5. After that you just need stuff to put in the bags. Oh, I bought those party favor bags, mesh, that people use for weddings from Amazon for $12 for a hundred. A box of Alfalfa, one of blood meal, and one of kelp meal were about $10 each. A 20lb bag of worm castings costs me about $17. That is all I can think about..though I just woke up.
But to be fully honest, I went a whole year doing teas and I am actually going to go back to bottle nutes this next year. The teas are great and once you get the correct balance, the plants love them, but the ease of just mixing a batch from bottle nutes and not having to wait or guess/plan ahead 24-48 hours is very convenient. When I say guess/plan ahead, I mean you have to gauge and really know when your soil is going to be dry/need-watering in a day or two from when you start the brew. It isn't too bad once you get used to it. But, like me, I have several plants and they don't all require watering at the same time either which makes it tougher. And my available time is depleting with my son now passing 1 year old, he is getting to be more and more fun to do stuff with and I find myself gardening a little less and less. Plus, the bottle nutes are super straight forward.
Not to dissuade you, of course. I would at least suggest trying everything and then choosing what works best for you!