I'm slogging my way thru act 2, and have entered Battlefield 2. The merchants seem to be rather strangely selective with regard to what items they will purchase. I've taken to "balancing' the funds on offer after each item I select to sell. Often, merchants will offer only a portion of the item I select to sell; sometimes they will offer nothing for a fairly valuable item. I've tried to ensure that I'm selling the correct item to the proper merchant (ie. armour to the armour specialist, etc) but that still doesn't seem to get a reasonable price after a unspecified point.
What am I missing?