As Manon said, we need to know where you lose your money on. Old players might be cheap on the transfer list, but they cost more salary per skill they provide as they decline during the season. I don't know how the market is for low end players, but it might be better to just buy 18/19yo's and train them. You can get a Superstar potential with 50 TSP (18yo) or 60 TSP (19yo) for under 50k if you look after the draft. Then you only need a lvl 3/4 trainer which costs less than 15k a week to train those guys. It takes longer, but you can save money in the meantime and you'll come out better in the end.
Staff could eat a lot of your money too, what are you paying them?
Expand arena and keep prices so that you sell about 90%-95% of each seat.