to save money u can use a reusable medium, reuse soil (once at most) , buy local composts/make your own, stop buying bottled nutes and brew your own (tea setup's initial cost big $$ but worth it. ) and by using methods that increase yield (airpots, airfloor, light spectrum, support lights, training) . I hear great things about supersoil, but i haven't tried it yet. this stuff will assure you that you get a great yield. But i've heard hydro gives an even better yield with less root space required. Also, when buying equipment get good shit so your not buying it over and over, and make sure you maintain your equipment (cleaning properly for instance, fixing problems, and replaing bulbs/ballasts)
when it really comes down to it though, you will get more $ for your harvest if your quality of bud is great and you can maximize yields. also don't sell your weed for less than you'd pay if you ran out, just isn't worth it (unless your not worried about running out). and yeah I've been thinkin about not smokin my harvest and seeing what i get $ wise that'd be cool shit.
when you want a big money turnover, id say the best thing to do is OUTDOORS! (organically of course)
with your saved $ you can buy nutes to make it easier for you to tend to the other things (insects, training, maintaining)
and with outdoors theres a lot to "keep up with".
picture 8 trashbarrels filled with dirt, and then giving them 1-3 hours every day
Also if you go outdoors the biggest enemy are pests. be sure to use a proper sprayer and good insecticides . as for organic insecticides there are hot pepper spray recipes but you need to do a follow up rinsing so the stigmata on the leaves aren't clogged up