if you want the lowest fare possible, yes. you can always cancel and get refunded the money. tip: check the airlines sites as well as the discount sites. i've been finding a lot recently going through the airlines is a better deal, but not always.
edit: i waited on it last year because of a job and ended up paying 600 to get to SFO and back, and the way out had 3 different flights. nothing was cheap by november. i was also flying from the east coast
Great, thanks so much for the response. I was under the impression that flights were nonrefundable unless I pay a lot extra for a refundable one, is this not true?