The hardest thing to get rid of is those silly commons/uncommons that no one wants. So you either have to sell them for a bundle super cheap or include them a deal with the higher end cards. If you can't get rid of them, I can take them off of your hands and donate them to new playgroups, obviously you aren't getting any money out of that, but if nothing else it will get them off of your hands!
Just as a side note, I tried to sell a ton of commons/uncommons at a penny a piece and they never sold, so connecting them to higher end cards is probably the best play!