I replaced my own a year or so ago for under $500 for the water heater and two hours labor.
It doesn’t require a lot of skill. Just remember : Righty Tighty, Lefty Loosey, and use teflon tape on the pipe joints (yellow tape on the fuel line joints if you are doing a gas heater.)
I feel sorry for anyone who can’t install a water heater themselves. I replace ours in about 1/2 hr myself. $329 at Lowes for 50 gallon electric unit.