I think what most publishers are looking for is fantastic writing and fresh takes on things. So yes, you should feel free to use the tropes of your genre, but you should also do your best to stand them on their head and make them new, different, and exciting.
Pricewise, my first novel, STAKED (coming out March 11th, 2008 from Pocket Books) is being released in trade paperback for $14... which seems to be pretty standard for new releases in that format, so I'm not sure that I'd worry too much about the $17. Spend all that angst worrying about whether people will like it when they read it and whether bookstores will stock it.
That's where I've funneled all of mine.
---Jeremy