if price is what's stopping you, i have a big tub of the stuff from costco for around 24$ if i remember correctly. it has only like 26g of protein per scoop so i usually put about a scoop and a half so i get around 40 g of protein.
if i was you i'd only take it on lifting days RIGHT AFTER you workout. Especially since you are tight on cash like myself, you shouldn't be taking it on off days.