Comcast last month announced that it was giving its Flex streaming device to Internet-only customers for free, but the announcement did not mention one important detail: the "free" device is only given to Comcast broadband customers who spend $13 a month to rent Comcast's xFi Gateway modem/router.

The Verge yesterday published a story that details the problem. The Verge wrote:

After the free offer was announced last month, a Comcast spokesperson told me the rental requirement would be dropped “in the coming weeks” so that all Internet-only customers could get the device for free. But a month later, that requirement is still in place, and Comcast’s checkout interface has even been updated to emphasize that its streaming box, called Flex, is only included when you rent the company’s modem/router combo, the xFi Gateway. The Comcast spokesperson now says the ability to use your own router and avoid the fee is “coming imminently.”

Comcast told Ars the same thing today, that it is lifting the restriction very soon. A Comcast FAQ explains that the Flex box automatically connects to your Comcast Internet service once it's plugged into a power outlet, as long as the Comcast wireless gateway is operating. Comcast told us that a software update coming soon will let the Flex connect to any Wi-Fi network.

The ability to connect to any Wi-Fi network is a standard feature in most streaming boxes, obviously. But for now, it's still impossible to get the free streaming device without agreeing to rent the Comcast modem and router.

You can verify this yourself by going to the Comcast Flex ordering page. The page says the Flex box is "included with Internet... at no additional cost," but the instructions say customers must "select our xFi Gateway modem + router at checkout" in order to get the "free" device.

Once you select an Internet plan and head through checkout, you'll see it's impossible to select the free Flex box without agreeing to pay $13 a month for the gateway. You can't check the box labeled "Get Flex at no extra cost" unless you first check the box labeled "Add the xFi Gateway for $13.00/mo." If you do check both of those boxes but then change your selection to "No, I'll use my own modem and router," the "Get Flex at no extra cost" box is automatically unchecked, and you can't select it again unless you switch back to the modem/router rental option.

Gateway rental fees add up

Comcast's Flex device is similar to other streaming boxes in that it lets you access online services like Netflix, HBO, and Prime Video. But the modem-rental requirement could make a free Flex device much more expensive in the long haul than buying your own modem and a different streaming device.

At $13 a month, you'd be paying $156 a year on top of your basic Internet service costs to get the modem and streaming box. Modem/router prices vary a lot, but it is possible to buy both a modem/router combination device and a streaming device like the Roku or Amazon Fire TV Stick and spend less than $156 combined. That would give you similar capabilities and let you skip Comcast's $13 monthly fee for years, potentially saving you hundreds of dollars. And that's not to mention the fact that Comcast repeatedly raised its modem rental fee in previous years and is likely to do so again.

Fortunately, the gateway requirement is going away soon. But Comcast could end up collecting modem fees indefinitely from customers who accepted the "free" Flex offer over the past month if they don't return their rented modems. Customers who already got a Flex box and Comcast gateway could swap the Comcast gateway for a third-party device and stop paying the monthly rental fee, but it's not clear whether Comcast will notify those customers that they can do that.

The forthcoming option to use Flex with non-Comcast gateways would also be useful for people paying for Flex boxes. Although the free Flex offer was just unveiled in September, Comcast started offering the Flex device in March for $5 a month. If you get the free Flex box, you can rent additional ones for $5 a month each.