I am a firm believer in buying second-hand. It not only saves you money, but also helps ensure everything that's produced is used to its fullest instead of dumped in a landfill with tons of life left.
I've been talking a LOT about our new puppy lately. I felt it only prudent that I mention precautions that should be taken with ANY new-to-you (but really used) pet items to be safe.
There is one nasty virus that puppies can be susceptible to if not properly protected. One of those protections is ensuring that anything you get for your new puppy is properly cleaned before it even comes in the house. Honestly, with pets running around the pet store, I see this as being a wise thing to do even with NEW pet items.
That nasty virus, Parvo, is best killed with bleach. You know I am ALL about natural when natural is possible. However, in some cases, it's best to go to the chemical. I wouldn't run to the doctor and demand an antibiotic for a cold, but you bet your BIPPY (yes I said "bippy") that I'm going to take one for strep throat. In the same manner, I would use vinegar, lemon juice, & my other "standards" for cleaning most items. However, when I have new or used pet items, they're getting washed with bleach before my new puppy uses them. To me, it's just not worth the chance.
So buy away on Craigslist, ask for what you need on Freecycle, or scour every garage sale in town...just make sure you are properly cleaning your great finds so that your pets are fully protected!