This is an super fun game! I love the strategy vs time management aspect of the game. Everything feels really good in terms of playing.
If you wanted to continue to build, I suggest adding a hidden limit to how many of a specific item you can sell. I kinda spammed making abstract art and made several grand pretty quickly at the market. Shadow mechanics that make the game harder or easier depending upon how much money the player has could also work well. This would make it easier to make money when you have little but hard when you have lots. I also suggest adding some end game goal, like trying to buy a car at the end of summer that the player can build towards.
Overall great game and good luck with your future game dev!