There are LOTS of different kinds of truffles, some are expensive, some aren't (relatively speaking). For example, Oregon truffles are generally a fraction of the European varieties partly because of all the shipping and middlemen. In fact, Oregon Truffles may go for just $20/ounce or less. Black truffles are usually more expensive than white ones, and Winter truffles are more expensive than the Summer varieties. Wild truffles are more expensive than cultivated ones.
Truffles tend to absorb the flavors that they are mixed with, so I doubt that any of the mainstream cheese manufacturers are using the high end (expensive) truffles.