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.
While advance purchase does allow a greater selection and the possibility of better prices, booking too far in advance could yield higher prices. Most travel experts agree that one to three months in advance is really the soonest you should purchase airline tickets.