|Unlock Forum posting with Annual Membership.|
It is against the rules to start a separate post on one of the genre forums offering deals from your shelf. What you can do though is check out the Book Bazaar forum, that's where anyone can show off their shelf and offer deals. Also, you can add your deal to your signature line and then it shows on every post you make, no matter what discussion board you're on.
Another great way to create interest in a book you've just read (and posted to your shelf) is our weekly "what are you reading this week" thread. I can't tell you how many books I've found from seeing other people talk about what they're reading and recommending.