You can buy even nicer material and much cheaper material but I found this to be a good happy medium.https://www.homedepot.com/p/Home-Decorators-Collection-Blue-Cedar-Grey-6-in-Wide-x-48-in-Length-Click-Floating-luxury-vinyl-plank-flooring-19-39-sq-ft-case-360486/304051044If there were hard wood floors under the carpet I ripped up- I would have chosen to refinish them with 4 coats of polyurethane.

I do my own contracting so my costs are a little lower, but a really really really basic rule of thumb i use for a napkin type estimate is  as followspaint carpet granite flip ( basic quick flip nothing major being done) -- $10 psf Remodel kitchen and baths ( keep cabinets but refinish them, and update the rest and paint the house)-- $20 psfNew flooring and the other above work no walls moved -- $30 psf Moving walls and all of the other above work through out keep plumbing electrical and siding-- $40 psfFull rehab new everything $50-60 psfAdding sq ft-- $80-100 psfTHIS IS VERY VERY ROUGH i do not recommend using this for anything other than a super quick guesstimate.

We refinished the original hardwood floors and installed new laminate plank flooring to compliment.

People always ask how I did certain things in my rentals such as custom light fixtures and refinished furniture. 

Renovated everything: floors sanded and refinished, completely new kitchen and floor, paint inside and out, simple landscaping, and perimeter drain in the basement.

I also paid for the hardwood floors to be refinished and the exterior aluminum siding to be painted and repaired.

@Camille Joos-Visconti I think if you become someone's colleague on BP, you can send a direct message.To answer your question, I spent $50k on remodeling the entire 2-bdm apartment, including new sheet rocks, ceiling, paint, kitchen cabinet, countertops+all new appliances, new flooring, new bathroom, re-finished all doors, new recessed lights....but I learned that I could save money on hiring a good GC, instead of negotiating with individual sub contractors myself. 

Agree With Jerry, I also want to add that in half-plex, the separate owner is responsible for the maintenance of his house.Painting the exterior parts, Refinishing or Replacing of roof, Installing a Fence and other individual maintenance, are the responsibility of the owner.

Swapping carpet to laminate or refinishing old hardwoods under carpet.With just a few rentals or less, tax software like TurboTax should be able to handle pretty well if you're looking to DIY.

I don't know how many units you have but consider picking a flooring type that will work in ALL your units to standardize the material selection process. 80% of our rentals have the original hardwoods refinished and ceramic tile in kitchens and baths.