Youll never get it dead on at home.

I have used a level to set camber, and then used a tape measure to set toe, but setting the caster setting (vertical tilt of the centerline of the ball joints) is nearly impossible. Camber and caster are adjusted with the same components (eccentrics on the upper control arm pivots) When you change one you change the other. The way to set them both is to make the needed adjustments for each at the same time. Tough to do on your garage floor. Could be done, but pretty tough.

Caster and camber are measure in degrees of tilt. they make level type camber gages, but not for caster (that I know of)

Toe is a piece of cake, its measure (usually) in inches of toe in or toe out, depending on the specs.

Caster being out of spec wont cause your tires to wear, but it will cause many handling issues, such as puling to one side, poor returnability of the steering wheel to center, and instability a higher speeds.

The needed tools to set camber and caster at home would far outweigh the cost of an alignment done at a shop.