Replace the small things
Replacing the minor items can also improve your bathroom instantly. These could be your toilet seat, bathroom mat, shower curtain and other things that won't break your budget.
You could buy some of these items new, but another option is to get them from thrifting spots.
Give your walls a new coat
With all the steam and moisture that circulates in the bathroom, the walls suffer. With time the paint becomes duller or even peels.
You can bring in someone to give your walls a paint face lift for a refreshed look. If you have some minor cracks that aren't connected to any other issue, you could get those filled in, in the process.
If you plan to do this, choose a color that will bring in more light and a shade that will make your bathroom look expensive.
Add some simple decor
The bathroom isn't the easiest room to decorate because of the moisture and water. But you can still make your space look better by getting some bathroom-friendly decor.
You can get some interesting towel hooks, a cool mat or even decorative mirrors depending on what you like.