If I were you I would:

1) Give the report away for free on a squeeze page, even record it into a video if you can.
2) Do a little PPC on medium to low-competitive terms on Adwords to build your list to a respectable level
3) Start doing Adswaps (i.e. cross promo's with other marketers to each other's squeeze pages/free offers)

I think this will be a good list-building tactic. I've never really used the $7 idea, although I'm sure it has its benefits!