Die Crack

coinyoungsta- It really depends on how major the crack is as well as myriad other factors relating to how common cracks are in that series, the the overall demand for that type of coin within the local market, & etc. I know that lot of collectors of US coins claim that they add value to a coin. By contrast, collectors of many other countries do not place an additional premium on error coins. In fact, for some countries die cracks and other problems are the norm.

What your asking is pending on the amount of error collectors in an area. At coin shows as a rule, any defect in a coin is shunned by the serious collectors that usually sit and study each coin as if it was going to say something. Many don't take coins with the slightes problems if they are looking for coins for a collection. The grade is not as important to many of those types of collectors as the condition dealing with dents, Cuds, die cracks, etc.
Contrary to that are the latest increase in error collectors I've noticed at many coin shows. Even some dealers have gone to specializing in all types of errors. One dealer at many of the coin shows I attend has two tables of just error coins and he charges outrageous amounts for them. He knows his prices are high but he does sell them. Die cracks, slight offsets, broadstucks and almost anything possible is selling really great for him.
So it really depends on who is buying what. I haven't been watching ebay for those but since I just about live in so many coin shows I see what is happening only in my area.

Really, really not a good idea to interfear in someone else's transactions at a coin show or anywhere else. A dealer could be a real nut and you could end up in a bad situation. A dealer may have many friends in other dealers and again, you could end up not being able to acquire anything. The buyer too may just be a plant by the dealer and blow his top at you for sticking your nose in. At shows it is not to uncommon to have a friend as a plant to make it look like your a great dealer. Same reasoning for people not going into an empty gas station, restaurant, etc. People like to go where other people go. Having someone hanging around a dealer's table makes it appear he is worth dealing with.
Over the years I've seen many things I didn't like at coin shows but also have well learned to keep out of those situations.

coin die cracks and their premium is up to the buyer. Here's a large 1884 British North Borneo 1 cent copper flipside with a horizontal die crack almost like a grin ear to ear

it's about to undergo lye bath cleaning for the learning process (mine) on taking out corosion maybe when it's cleaned, I can see the die crack much better

actually I paid less for my 1868 Shield nickel in EF/AU, it has a die crack completely around the shield and through some of the letters. I found the cracks on accident, my dog has black hair and sometimes the hair will get stuck on the slides in my 7070 and I went to wipe it off and it wouldn't come off so I got the magnify glass and saw the cracks.