I saw this today in an online news article about the recent launch of the Sprint XOHM service in Baltimore, Maryland.

Problem:
An apostrophe is missing.

Explanation:
The complete sentence was You can attach one of four service plans to your XOHM devices: The “home” plan works with the home modem, for 35 a month (its on sale through December 31st for25), the “On the go” plan is for the ExpressCard, at 45 a month (30 on sale.), and “Pick 2” lets you get two devices (a modem and a card, for instance) for 65 a month (50 on sale).

The word “its” — spelled I-T-S — is a possessive pronoun.

The article writer is trying to say that the home-plan service is on sale through December 31, 2008, with “it” substituting for the name of this service.

In other words, the expression should have been written with the contraction form of “it is” in “… it is on sale …”.

Solution:
“… it’s on sale …”