Mr. Martin McSorley:

The margin we make is typically 5 cent. On a good day, it might be 6 cent.

The reason some sites are selling and buying at the same price and some are selling with a difference is on some days it was the same price to buy it. If someone bought stock on the 9 March, there was a 10 cent difference between the two. However, if he or she bought it on the 8 March, there was only a 3 cent difference between the two. That is why they are selling it on that way.