you can take merchant offers through the trader, as they all appear on the same area. but as others noted, you can only place trades via the merchant. depending on your particular boosts, i highly suggest doing both, fairly continually. it's fairly normal for me to take aerosols with my wax, even tho i need powder, because i can just turn around and pick up an aerosols for powder trade. ascended goods take a lot of attention to swap around.