Looking for a cheap way to finish osb floors

https://www.doityourself.com/stry/how-to-paint-osb

Unless you used exterior grade OSB it will be very suseptible to water damage like swelling and flaking. I would use a somewhat dark oil based stain to color it, then apply a coat or two of exterior polyurethane. You can lightly sand off the writing, but the seams will still show. Use a couple of throw rugs until you can complete the job.

Try the paper bag floor covering.

I also thought paper bag floor Here's a cool tutorial! https://www.hometalk.com/diy/floors-ceilings/paper-bag-floors-1147044

You can also try looking for lock tiles. They are pretty cheap and easy to install.

I've found paint in the color I wanted floor to eventually be and painted on a few coats. Its cheap, held up decent, and you find out if thats really the color you want to pay more to live with later.

paper bag floor or stencil the surface