said by andyross:
But, you can't just simply buy an eMTA and use it. Comcast is VERY picky about eMTA's, supposed due to e911 issues. If you cannot do it through BestBuy, they will probably not provision any eMTA you buy, at least not the phone part.
This is correct. I work for Comcast directly in a Best Buy store. The only place you can buy the modem is inside a best buy with a Comcast Connection Center. If you buy it anywhere else they will not provision it. The tech or dispatch can not get it provisioned for a account. The modem has to be provisioned through a chat link only the Connection center reps have access to.
If you somehow find a Arris TM722G/CT online cheaper than 149.99 you can bring it to a Best Buy w/ Comcast and ask them to add it to the account. It has to be brand new (not used) and only that exact model. I've already tried getting a different model provisioned for a Customer and they would not do it.