What would be a good cheap window covering for a bathroom window

A homemade curtain. Can be made out of a sheet, shower curtain, spare fabric, pillowcases, etc.

Hi Regina, Along as it's not in the shower, I've used blinds, shades & curtain tiers - cotton or a blend of polyester & cotton. You can also get privacy window film from places like Home Depot, Lowes & Amazon that you put on the glass to give privacy but allow in light in. Click on the link below to see some of the privacy films that are available. Wishing you the best.

https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=privacy+windows+film

I bought a window kit for making faux stained glass window at a local hobby lobby and covered our window one time. They have samples of the picture you can make, but I took mine from a coloring book and copied it onto the glass. We like western scenes and it was a profile of a coyote howling at the moon with the moon/sunset and desert scenery. It turned out beautiful. You could use a kit or use any color book lines, they are simple and easy to trace. Some people like flowers, butterflies, fairies, there are limitless choices in coloring books and they are inexpensive. Walmart has some window stain kits also in the craft dept. Hope this helps.

Forgot to mention, another thing we did in another home was to put up bubble wrap on the window. It kept the cold out in the winter and the heat out in the summer. We left a few inches at the top is all to see out but you would not have to. The whole window could be covered. Bubble wrap is inexpensive and lets in the light but not any vision of what is behind it.

Here are some more ideas:

https://www.remodelaholic.com/25-diy-window-coverings-tutorials/