I had to remove 5 rooms of carpet. I need to find a cheap and easy way

An easy way to do what? Please

Your carpet needs to be replaced. The pad underneath in not any good anymore either. The least expensive flooring ie either vinyl tile squares or laminate flooring.

Since its a rental, you need to make sure the landlord is good about what you do. In fact, you could probably get the landlord to replace it.

If you have wood floors underneath, just refinish them. If a rental, people will pay more money for wood floors (provided the rest of the house is up to par), and get a better quality, long term tenant.

Can you use plywood to finish floors and what do you use to stain it with?

Hope you got permission from the landlord in writing. Cheapest and easiest is vinyl plank flooring.

It's not for everyone but I needed an inexpensive floor covering for my condo after ripping out 30 yr old carpet. Home Dept sells 18" carpet tiles that are indoor/outdoor and they're kind of sorted by palette (grays vs beiges). They end up being about a dollar a tile so I bought enough for the bedrooms. You will have some throw away tiles that don't work so those are good for the closets. They end up looking like men's suiting (I think) and look a lot better than I expected. Also, since I have dogs I liked that they're indoor outdoor and easy to replace. You can also order tiles at Lowe's for closer to $3 a sq. Ft. if you want softer flooring. This was an excellent option for a few years until I decide what to do. After I did it I kinda fell in love with it.