The amount a Trek bicycle costs depends on the design and building material of the bicycles frame and the components used to create the rest of the bike. On road bikes, such components include brake mounts, the front fork and the fender mounts.
Most road bikes use cantilever brakes, and the addition of disk brakes to a Trek bicycle increases the price of the road bike. Custom handlebar pads increase the price of road bikes as does internal cable routing. An upgraded decoupler adds to the price of a bike, and additional speeds over the traditional 10-speed gearing costs more money. Trek bikes with drop bars are more expensive than those with traditional handlebars.
In mountain bikes, the type of suspension is also a big factor in bike price. Full suspension bikes, which have shock absorbers for the rear tire, cost more than front suspension bikes. The quality of the suspension has a large impact on the cost, and spring suspension models cost significantly less than gas suspensions. Whether the suspension can be adjusted or "locked out" also increases the price of the bicycle. The type of brake influences the cost of a Trek mountain bike as well. Mechanical disk brakes are less expensive than hydraulic disk brakes. Other features which increase bicycle price are drop seats, internal cable routing and carbon frame armor.