truffle oil IS truffle infused oil, and i guess you pay as much as you want to depending on quality.
Truffle
By weight, this knobbly fungus is one of the most expensive foods in the world. Although attempts have been made to cultivate truffles, the majority are still found wild, growing around the roots of oak, chestnut, hazel and beech trees.
There are two main types: black (Tuber melanosporum) and white (Tuber magnatum Pico). The finest black truffles are found in the P�rigord region of France; the best white truffles (in fact they're more beige) in the Piedmont region of Italy. Truffles are sniffed out by pigs or dogs trained to recognise the smell.
Black truffles are peeled and can be used raw or lightly cooked, while white are just carefully wiped clean and should never be cooked. They have a distinct peppery taste and are usually sliced raw directly onto the dish. You can buy a special slicer that cuts razor-thin slices, or use a mandolin.
The truffle's unique aroma and taste does something magical to foods - shave it over pasta or add it to scrambled eggs, omelettes or risotto.
Truffle oil is the next best thing - a combination of olive oil and truffle extract that can be drizzled over pasta, risotto and salads or used in salad dressings and sauces. There's no substitute for the unique taste of a fresh truffle though.