Renting modem 7.99 X 1 yr. = $95.88. 10 years = $958.88. 20 years = $1917.60. Won't even go to how expensive total bill is @ 20 years.

I copied-and-pasted my comment from another post.

"You don't rent a standalone modem.  You purchase it.

If Cox comes to your house to initially install your Internet service, they'll charge your bill for a modem.  You can rent a router from Cox (Panoramic), which includes an Internet and phone modem, but that'd be the only time you'd rent one...that is, to partially rent one.

Cox has a list of "certified" modems for their network.

https://www.cox.com/residential/support/cox-certified-cable-modems.html

You don't have to purchase an Internet modem from Cox.  You can buy it anywhere you want.  Just ensure it's on the list of approved modems.

Also, don't buy somebody's used modem because Cox has them identified, logged, archived...or something...I don't know.  I read a post about a subscriber trying to activate a used modem but Cox wouldn't do it.  I think they just want to sell modems."

https://forums.cox.com/forum_home/internet_forum/f/internet-forum/21562/upgrading-modem

Could you be renting a router from Cox?  If you already have an Internet modem, you previously bought it.  If you're renting an all-in-one device from Cox (Internet modem, telephone modem, wireless router), you could save money buying your own router.

If you bundle services (Internet, telephone, TV), at the most, you'll need 3 pieces of equipment:

 - Internet modem.......you purchase
 - Router.......................you purchase or rent
 - Telephone modem...free

Well, 4, if you count the cable box...you rent.

If you have a standalone modem, you're good to go to return your rented router to Cox.  Buy your own router beforehand.  There's plenty of advice here to recommend a good router.  You could also leave your telephone service connected to your standalone Internet modem, if required.

If you're renting an all-in-one device and tired of rental fees, you'll need to return it to Cox.  If you have telephone service, get your free telephone modem while you're there.  You'll need to purchase an Internet modem and router beforehand.  You don't have to purchase these at Cox.  Just make sure it's "certified" to work on the Cox network.

Free all-in-one device?  If you're lucky, Cox will be out-of-stock for standalone telephone-modems.   However...by law...they have to freely issue you something for telephone service.  As an alternative, they'll issue you an all-in-one device.  It's all they have.

In essence, by returning your all-in-one deice, you're tired of renting, Cox will take it, update your account and if you have telephone service, they'll issue a telephone modem.  (Oops...Cox doesn't have any).  They'll either return your all-in-one device or issue you another all-in-one device...FREE!