Publishers Marketplace. So far, it has been worth the $20. It's really useful. You can watch big fancy book deals go down as you sit at home transferring money from the savings bond you got when you were 12 to your checking account so you can have air conditioning this month.
But seriously. It's good, because you can see what deals the agents you're querying have made recently. You can find out which agents represent which authors. And you can learn all the insider speak (you know, words other than "book" and "write" and "PLEASE I'LL DO ANYTHING").
Also, it cleared something up for me. In my web travels, I kept coming across the verbiage "good deal," or "nice deal" or "very nice deal" and so on. I thought this was just agents being sweet. Like, "Check out my super-neat deal, flowers and rainbows, yay!" But apparently, those words stand for cold hard cash. Publishers Marketplace explains:
Nice deal = $1 - $49,000
Very nice deal = $50,000 - $99,000
Good deal = $100,000 - $250,000
Significant deal = $251,000 - $499,000
Major deal = $500,000 and up
So you see, next time you hear an agent or writer say "major," they are not just fond of Victoria Beckham (though, I can't imagine why they wouldn't be). They are HAPPY. SRSLY HAPPY.