Most gas water heaters fall between $400 and $600 at The Home Depot, as of March 2015. The majority of electric water heaters cost between $300 and $400.
Electric water heaters are less expensive than gas heaters, ranging from $200 to $1,300. Gas heaters cost between $300 and $3,000. Most consumers can expect to pay between $300 and $600 for either type.
The price of a water heater depends largely on its capacity and heating power. The Home Depot's most expensive gas unit has an 80-gallon tank and puts out 76,000 BTU, while its least expensive gas unit has a 40-gallon tank and puts out 36,000 BTU.