I have a Motorola/ARRIS cable modem for sale in perfect working condition.
For Comcast subscribers, this allows you to get your cable TV service and internet service. All this for $25, and you can stop paying monthly fees to rent the same or similar device from Comcast.
The model and its specific features can be found at https://www.amazon.com/gp/product/B004XC6GJ0/ref=oh_aui_search_detailpage?ie=UTF8&psc=1.
Note this will not provide telephone service with Comcast (if you have their Tripleplay bundle), nor does it act as a WiFi router.
Contact me at firstname.lastname@example.org if interested.