As with any other major purchase, if a deal seems too good to be true, it usually is. Some schools base their prices on the FAA minimum-time requirements, such as 40 hours for a private certificate. Others base their prices on a more realistic figure that's the average of what their students accomplish. Some include books and supplies, ground school, flight testing, and FAA written examination fees. Because most schools require partial or full payment before training begins, financing your flight training, especially if you are in a professional pilot program, will be your greatest challenge.
Some schools offer financing, and most have financing and loan information.
AOPA, for example, offers its Flight Funds loan program to its qualified members. Some schools guarantee their training - that you'll earn your certificate for a fixed price no matter how long it takes. Read the fine print carefully, because many of these guarantees expire after so many flight hours. If you haven't achieved your goal in this time, the school will still train you, but you'll have to pay for the training that takes place above the guarantee's ceiling. Also inquire about refunds.