Chalkboard paint is an awesome product where you can turn just about anything into a chalkboard. But if you want to do a great job you will usually need 2 coat, if you have a large area you want to do, such as a whole wall it can get expensive.
If you are a DIYer you can make your own chalkboard paint and save a few dollars.
Here are the materials you will need:
Latex paint – In what ever color you desire.
Dry Non-sanded tile grout – use a neutral color especially with light color paint, any brand will do! 
Mixing bucket – 2x bigger than the amount of paint you need to mix.
Mixing device – If you are mixing a small amount a paint stick will do, if you need a large amount I recommend a mixing paddle attached to a drill.
Brush or Roller – A low nap roller – 1/4″, and a good brush, foam brushes work well.
Sand paper – 150 – 220 grit. You may need to lightly sand board if it is rough when finished
1. Mix the latex paint with the non-sanded grout in a cup or bucket. A good ratio to use is 1 part grout to 8 parts paint. So, if you’re mixing a small amount, mix 1 tablespoon grout with a ½-cup paint. For a larger amount — like I used — mix 1 cup of grout with a ½ gallon of paint.
2. Paint the surface with the chalkboard paint. Prep the surface as you would for any paint job. I painted two coats for even coverage.3. Condition the chalkboard. Get your chalkboard ready for drawing by rubbing the board with chalk, then wiping it off with a dry towel in circular strokes. With that final step, it’s ready to be put to good use.