One of the most important things about owning a comics and toy store is staying on top of trends. You have to keep your prices with market and know what collections to be trying to purchase. Right now there isn't much hotter then back issues of Dark Horse Star Wars Comics. Below are a couple that go on the "wall" tomorrow for sale.
If you have any old Star Wars comics sitting around the house now is the time to sell IMO. Always sell while something is hot!
I have a complete set of Dark Empire and Dark Empire II around somewhere. I think those were among the earliest Dark Horse Star Wars comics.
If they aren't something you are attached to it might be time to consider selling. Dark Horse Star Wars comics have gone from "who cares" to crazy hot over the past year. Don't honestly think it's something that can stay at these price levels...but who knows.