Digital Manga is offering a “September Switch” promotion. If you
a) have bought an eBook somewhere else
b) register a new account with them (new customers only)
c) use the same email address for both
d) send them a copy of the receipt from the other store
they will send you a gift code worth $7.95 at their site. The offer is good through October 13. The iffy part for me is them wanting proof of your purchase from another site — what kind of information are you willing to reveal for a free digital book?