I talked about Boom’s Giant Days before in this post about the bleedingcool Effect. Giant Days was heavily speculated and jumped on when the first issue came out but like many all-age comics the consecutive issues had a much lower print run resulting in those issues to be selling upwards of $20 to $25. This was corrected by the published by printing more copies when issue #4 and #5 came out, however, Issue #2 and Issue #3 are books to be looking for.
Giant Days #2 sells for $15 to $25 while Giant Days #3 steadily sells for $18. Both of these books are still available on the Boom Studios website at cover price. International shipping from this website is expensive but worth it considering the potential profit.