I agree with Hoss.
The special tools needed, the knowledge needed, the experience needed is not for the faint of heart.
Although you won't save money, there is still the satisfaction of "I did it myself".
Check the frame and slide combos at www.brownells.com as a starting point. For most, you could buy a complete pistol for the price.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)