GW store

is the stuff u can get at the gw in store worth it eg extra character slot?

40 slot mules worth $10 to you? Everything's worth the price, but it's up to you if you want to pay for it.

My only complaint about the store is their lack of merchandise. I would buy more if they had more to offer.

If you want another character, then it's worth it...

Anything is only worth what it's worth to you. But, I suppose you are really asking if we think it's worth it.
The problem is that, to me at this time in my life, $10 for a character slot is nothing - it's basically free.
The price for the games/campaigns in the store is essentially the same as buying them somewhere else - so that's not a matter of whether or not it's worth it in the on-line store in particular.
The only things I have bought through the on-line store are a Character slot, the EoN expansion, and the game-of -the -year update.
The character slot was well worth it - I use it as storage - but it just depends upon what you want it for.
The EoN expansion was the same price as the local game store - whether or not EoN is good value for the money is debatable.
The GotY expansion, at the time, just gave you the extra custom/collector weapons that came with th GotY edition of the game. In the long run, it wasn't worth it. But, it's not available any more anyway.
I have no interest in any of the PvP stuff, so I can't comment about their "value".