double-blind study - an experimental procedure in which neither the subjects of the experiment nor the persons administering the experiment know the critical aspects of the experiment; a double-blind procedure is used to guard against both experimenter bias and placebo effects.
No they get more expensive, airlines will always advise you to book in advance to take advantage of their best fares. Sometimes they do a special deal but not within a week of flying. I would try another airline or make different plans.
Booking tickets in advance can help get flights at a lower price. Rick Seaney, CEO of farecompare.com, recommends buying tickets around four months before you plan to travel. He says that airlines don't usually release cheaper tickets before this time but, when released, reduced seats are likely to sell quickly.