If I were you, I'd consider a couple of things before shelling out the money. The cost for new generally runs $100+ and comes with extra accessories (ie bassinette, changing table, mobile) that you may not need. Plus, it is likely that your son may not be fitting into it for too much longer.
Is this going to be your only child? If so, I'd consider checking garage sales or resale shops for a second-hand one (heck, you may even find someone here who is looking to sell theirs on this site). Chances are he'll only get months (vs year) use out of it depending on his height. Course, if you're having more children, you will obviously have the chance to get more use out of it. (I've had several friends in two-story houses who used it like a bassinette when their newborns came home and it saved them tons of running up and down stairs for every little squeak. And now that I've had my second, I intend to set ours up in the shade outside when big sister is outside playing/swimming.)
Also, something else you may want to consider, I don't know how tall your son is, if he's walking or not or if he's much of a climber, but I would definitely take that into condsideration before purchasing one. The more nimble/clever kids can find their way out...
Hope this offers some perspective. Good luck with your decision!