Supposed you will reach level 100 then it's about 130 skill points totally:
- You will start with 2 native skill points.
- You will get 1 skill point per char level.
- You may get up to 9 skill points by quests per merc, vet and elite mode.
But don't fall now in 'skill point paranoia' (this is not Diablo 2

).
You will see soon that 'maximizing a skill' doesn't automatically mean 'optimizing a char' since instead of eg. the 17th skill point in a specific skill you often will find better alternatives on other skill-tabs.
In practise it's probably the best to focus on 10-15 skill points on a skill resp. to set this amount of skill points manually during the hole gameplay.
That will allow you to reach level 3 for most powers and leaves some buffer for skill points provided by items.
In emegency cases keep in mind that with the Broken World addon you can reset your skill point allocations, and without the addon there are mods to do this too.