Cable bills have a way of starting out expensive and then getting even more expensive as time goes on. This is especially true when cable companies offer promotional rates that last a year or two without telling customers what they'll actually have to pay once the discounted rate expires.

No cable customer is immune from this phenomenon—even outspoken telecom analysts like Bruce Kushnick are in for bill shock. Kushnick, a frequent critic of Internet service providers, signed up for a Time Warner Cable "Triple Pay" package in 2012 and is now paying more than double the advertised rate.

"When I signed up, less than two years ago, it was advertised at $89.99 and today, less than two years later, the actual price is 110 percent more—now $190.77," Kushnick wrote today in the Huffington Post.

For new customers signing up now, TWC's Triple Play TV, Internet, and Phone package has an advertised rate of $109.99 per month for the first 12 months. Another $20 per month is added in the second year, but it's hard to predict just how much it would cost two years from now. "After 24 months, regular rates in effect at that time apply," the fine print says.

Kushnick never paid as little as $89.99 because a variety of fees raise rates well above advertised ones from the start. Taxes, fees, and surcharges accounted for $16.79 in his latest bill, while set-top box and modem charges accounted for another $17.24. "Fact is—you can never, ever get the advertised price because it doesn't include many of the fixed costs, like the set top box, not to mention it is littered with pass-throughs of the company's taxes and fees, including the cable franchise fees," Kushnick wrote. "To add insult to injury, there are a bunch of garbage, made up charges, and let us not forget the increases on all services—the 'Internet modem' fee went up 140 percent... This bill is like going to a restaurant and ordering the $20.00 dinner 'special' only to get a bill of $38.68, not counting the allowable taxes."

Time Warner Cable argued that "Comparing $190.77 to $89.99 just isn't an apples-to-apples comparison" because of all those extra fees. "The $190.77 total price at the bottom of the bill includes all equipment, taxes and fees," a company spokesperson told Ars. "The $89.99 promotional price does not, and we are clear that promotional prices we advertise on TV/online, etc., do not include equipment, taxes and fees, because a) equipment can vary greatly based on customer interests and b) most taxes and fees vary from place to place."

The current regular price for the package Kushnick subscribes to is $156.74, the company said. Thus, he received "a roughly 40 percent discount during the promotional period—which is designed to give customers a chance to sample our services at a discounted price for a certain amount of time, then decide what package of services matches their interests and budget." Customers can rent a modem or buy one from a list of compatible devices.

Time Warner Cable is in the process of merging with Comcast, the only cable company in the US that's bigger than itself. Kushnick called for forced rate reductions given that cable companies effectively "have a monopoly over the cable wire." Comcast has admitted that cable companies rarely bother competing against each other because it's too costly to lay new cable in territories where a cable company already exists. There's little in the way of competition or regulations to force prices down.

"ISPs consistently are allowed to bury all manner of nonsensical fees below the line, allowing them to covertly jack up consumer broadband bills while leaving the advertised price the same," notes Karl Bode of DSLReports, who has written extensively about these billing practices.

Kushnick posted a marked-up image of his latest bill:

He pointed out his favorite part: "Enjoy the $28.20 you saved over retail rates this month."

Listing image by Bruce Kushnick