n00b question - Skill Trainers

Can I get some skills only through skill trainers or will i get them later on during some quest? Cause I don't want to waste an attribute for a skill .

Yes, there are some skills that are only given by skill trainers. As for the majority of them, you can get them for rewards for doing quests.

Well you dont waste an attribute for a skill, you buy one with Skill points which are very easy to get, my monk has like 10 left out of 100 but im just trying to unlock every skill in the game. So if you need the skill I would buy it, if you dont then just wait untill you want to unlock it or need it.

In most cases, when a skill is available from both a quest and a trainer, you won't run across the trainer until you've already been past where the quest is given. So if you're really worried about wasting skill points, just do every skill quest as soon as you get it.

Frequently the skills you can only get at a trainer are at outpost's that are out of the way. There are quite a number of outpost's throughout the game where there are skill trainers who offer skills not available anywhere else in the game.

Grendich Courthouse is a good example - it offer's skills that are not available via quest's.
Fisherman's Haven is another
Maguuma stade is another.

Although this isn't true anymore seeing as ANet decided in their "wisdom" to make things a lot easier and just make these skills available in the next major town.. so as lazy bums who didn't want to bother going to these outpost's could still get the skills..

Like now the skills you get at the Courthouse are now also available at Yak's Bend... pfft!

all skills are at ember light camp (except elites)

of course, most people dont know what the **** ember light camp is