as simple as this is i love the format and as for the concerns with the oils and massage locations i doo belive that either increasing the effectiveness of the locations so you can get more $$ or by having the girls give more money or the oils becoming cheaper is a nessicary thing unless you'd like to spend from a player's point about 6 sessions or so to save up for a big buy that only lasts 2 session. Other than that improve on what you have and this can be a solid game!
Very nice! Im glad! this game has potential. Just make sure you cover all your bases first and get stats working out in a way that doesnt take a few 20 minute tries for one girl, and i'd then work on making the animations and what else you plan to be the pay off for players investing in aphrodisiacs'. Perhaps they pay your more and unlock a different scene. there is allot of options you can take this.