Can you/Where to sell email addresses?

I've been lurking BHW for a while and am getting ready to sell my first product. I plan on selling an informative eBook, but giving the customer two options to get the eBook:

1) Simply pay for the eBook (something like $5), or…
2) Enter their email address, in which they'll receive an email to a link locker to fill out an offer, which upon completion will take them to the final download link (hosted on Blogger)

I'm wondering 1) is it legal to sell email addresses you obtain through an…

Can you/Where to sell email addresses?