It's $7 a month here also. I am tempted to purchase a modem and save the $7 /month
You could do that at any time really, so if you want to hold off until you can find a good deal, you can. I'm cheap, but after going through so many modems with (ugh) AT&T, I decided to just lease it and enjoy not having to worry about it should lightning/power surge knock it out or something (which has happened to me before).
Glad you didn't go with AT&T U-Verse. They charge out the wazoo compared to what they "say" they'll give you. My dad learned that the hard way unfortunately.
At home, AT&T was charging us $33/mo for a 1.5Mbit DSL line, having incrementally increased the bill throughout. Not sure what the hell their problem was, but we're with Comcast paying $20+7/mo for a 20Mbit line that is actually giving showing a 24.5Mbit connection according to all the speed tests I've done.
Hope they get your issue sorted out!