so to get access to use mercs I need to buy the merc unlock with 1500 SE right, but then I read somewhere that mercs came with an expansion, so would they also unlock if i buy the latest expansion? or do I have to pay the 1500 SE no matter what?
you have to pay the 1500, for an account wide unlock for mercs. the new expansion lets you use (a pretty awesome) special merc that you wouldn't be able to recruit otherwise.