Lowes has Whirlpool 50-Gallon 6-Year Tall Natural Gas Water Heater List price of $525 which is the standard price a water heater with these specs. Equivalent Rheem is listed at $607 at Home Depot Here is an extra (one time use) 10% Coupon code I’ll share with you.
Lowes has several other options for water heaters discounted 10-15%
Keep in mind water heaters need replacing anywhere from 6 years old and up.