I'm going to go a bit off topic here, I know you are asking about high speed internet prices, but in the spirit of ditching TV....
You can keep basic cable TV for ~$20 a month - I know it doesn't help with commercials exactly, but let me describe my setup. I have a small low powered book-sized server that I installed MythTV on (Mythbuntu, a linux distribution designed for MythTV, it's easier than it sounds). Additionally I have a HDHomeRun unit, this is a network based TV "card" that is picked up by MythTV and just works. These two make my centralized "home brew" DVR. I also added a couple external USB drives for 3TB total space. All my DVDs get ripped and copied here.
At each of my TVs I have another small/cheap booksize computer mounted behind the TV plus a cheap MS MCE remote control. I recently switched to XBMC as the front-end software. You can install XBMC in windows, in linux, or use something like OpenElec which while Linux based really turns your mini booksize computer into a set-top-box appliance. This is where the real slick part starts - there are plugins for all kinds of things. The obvious one is for MythTV - giving me full PVR capabilities, watch live TV, watch recorded TV (FF through commercials or you can tell MythTV to just remove commercials after recording stuff), access to all my movies, Hulu plugin (which somehow provides the option to skip Hulu commercials), music, weather, news, youtube access, etc. etc. etc. While I don't advocate them, there are also plugins of questionable legality - the ability to download or watch pretty much anything. If you really need to, you can even launch an external program (ie Netflix/Amazon prime) from the menu. Between basic cable, Hulu, and buying several hundred movie/tv series DVDs (Blockbuster previously viewed DVDs FTW) I have no use for the questionable options, but reading between the lines you wanting to dump cable tv and needing high speed internet...
If you don't want Linux in any way, you can just install XBMC in windows and use one of the Windows based PVR backends. Or not have cable and a PVR backend at all. In any case, do yourself a favor and look into XBMC, it has far more functionality than any cable/sat provider's set top box and still gives you the ability to sit down in front of your TV with a simple remote in your hand and watch whatever you want. Although if you go with no cable at all, it may be easier to just buy something like a Roku 3. A cheap set-top-box with hundreds of "channels" available including Hulu Plus, Netflix, Amazon Prime, etc..
Back to the original question - just look on the Comcast site for individual pricing. In my experience, dropping cable is not going to make your monthly bill go up, but you will lose out on the "bundle" pricing so your monthly bill probably will not drop as much as you expect.