So I want to try Pricelines name your price thing, but I have a couple questions.

How cheap should I go? 50% too much? 40% too much? The tickets I want to do are 421 right now(After fees and shit)
What if I submit a bid, but then the tickets go up and I buy before they go up again in fear they won't take my bid, can I cancel my bid?
How long does it take to find out if I get the tickets or not?(I'm buying 1 and a half months in advance)