A CGC Certified 7.5 copy of X-Men #1 with off-white to white pages realized $5,511.44 after receiving 38 bids on eBay. The Silver Age Marvel key featured the first apperance of the X-Men and Magneto.
According to the the CGC Census there are 2,018 copies that are certified with two copies tied at 9.8 as the highest graded.