$3 for a 20oz bottle...I think you will be able to find enough pocket change in the park during bootcamps for this one.
Find it at any local health food store. You want the "Raw Unfiltered with the Mother", organic is a bonus too....but no other kind will do.
Good luck getting it down.....it's rough. Oh yeah, don't take it straight (you make that mistake once). I usually say 1 tbsp in 8oz of water. If you are brave and don't get sick on more, you may be able to build up to it. But....good luck.