I don't know where you get Oregon truffles are more expensive than European.
A pound of fresh, best quality Oregon black truffles is about $215/lb (you have to wash and brush yourself) over the net. I called a couple of caviar supplier (that's who sells truffles) in SoCal and priced fresh French and Italian black truffles at anywhere between $600 - $1,200. The price differences seemed to depend on a lot of factors -- mostly rationalization and whining. The $600 guy was very firm in his price, while a guy who opened at $925 crumbled to $575 when I asked for an Southern California Auto Club discount. They must be sitting on a lot of truffles because the joke wasn't all that funny. At a guess, the low price was around cost plus 20% which is pretty fair.
In smaller quantities, say 3 oz, Oregon truffles, black or white, are about half the price of the Euros. Chinese blacks are about 10% to 20% cheaper than the Oregons -- but they're really inferior.
Just in case you didn't have enough to worry about -- some dealers will sell you Chinese blacks as French or Italian. Know your truffle, know your dealer. Shir shir.
If you really like truffles, you should try huitlacoche, aka Mexican corn truffles. They're not exactly like truffles, but they have enough in common to make a really interesting substitution -- and they're cheap enough to use now and then in things like scrambled eggs.
When you use truffles, the general rule is: Remember! It's all about the truffle. In other words, plan to push the truffle flavor and aroma front and center and use everything else on the plate in a supporting role. But that's general -- not hard and fast. I've successfully (IMO) used truffles far enough in the background that diners aren't aware at first that their brisket was injected with a truffled infusion before barbecuing (low and slow/oak).