Right now, getting through IV division seems pretty easy. There is no actual need to buy players. If you bought a player as an investment, a youngster, then that´s just fine, you shouldnt feel preasured by your financial situation because you have potential income to make things okay, but if you bought any player over 20 years, then you lost money on a long run and instead of winning your matches by 10 you'll win by 30, which looks pretty much the same to me.
I started off on div IV just as well, hadnt had anything lighter than anyone and my finances were ALWAYS just fine, I dont remember having less than 150k and right now I have 1,6M.
No secret really, I have very few players, which keeps my bill light. I rose the ticket price gradually until it reached the maximum without losing too many fans on the way, and always increasing my income on games, I hired a level 10 PR-Manager as soon as I had the chance and when courtside seats started to sale out I built more of them, and am still building, until the demand is filled.
I dont think theres any magic there, its really just a matter of taking the time to think of a nice financial strategy.