if you can afford some solo cups then you can afford a 3 gallon pot they are like 1.50 at my hydro store. go get you a pot and some CFLS.
you're not going for yield so they will do you just fine and if you ScROG your plant you CAN get a lot.
look up and do some research. Yes plants will grow with dirt water and light, but its gonna be some shitty shit. you're going for quality so get you a good strain and some good nutes. (flora duo series is cheap).
you'll be glad you looked into it