Most people learn two scales to start off:
-Major Scale
-Minor Scale
Learn those two scales in all their positions. Then you can try the Minor pentatonic.
Take your time, it`s OK to know three scales and use them correctly; than learnig so many scales that you never use, and then you can`t even remember their names.

Practice your escales over a simple chord progression, using a metronome or a drums machine.

After you have memorized your scales; start jaming, make sure to spread the notes so you don`t sound like playing "scales exercises".