I'm assuming you have a gunite pool.
If you are serious, there are two ways to go, a 2 part epoxy paint (see the Ramuc website) the best ones will go 8 years with proper prep. Power wash, scrub, acid etch, neutralize, power wash, dry, moisture test, then 2 coats at certain temperatures, certain timing.
the alternative is a proper resurfacing with a skim coat of gunite, best left to a professional.
I went the epoxy route in my last house, made it as far as the final prep step, and sold the house, gave the paint to the next guy as a freebee.
Materials cost for the epoxy way was 1200 in paint, 200 in materials, brushes, mixers, acids, neutralizers etc. Don't forget an organics repirator, a GOOD one. Total time was 2 weekends, sunup to sundown, by myself. Already owned a powerwasher.