You have to weighed first the pros and cons between the two as well becoming open mind on possibilities. Also make sure you are not one sided when you do that.
Anyway, moving forward to the question, here are my own opinion between the two.
Buying any new gadgets as new as never been used doesn't mean will cost you a lot. There are cheap gadgets out there that you can buy as well if you have coupons that normally the stores use for discount. You can also buy on holiday season such as black Friday so you can buy 50% to 70% OFF. Also having said as new, normally you have this so called Warranty where in case during the scope of terms of usage something bad happen without intentionally or unintentionally then you can replace it for free or they can fix it for free of charge.
These are good when you have this very good skills criticizing the product itself. What I mean is in and out, you can easily tell if the gadget you are buying is good as new or the owner itself take care of the gadget. I tend to ask some questions like, how old the gadget is? , are you the first owner? , is the gadget had history repair? and etc.. And once you notice that they lied to you even once in your sets of question, do not buy it. It will be becoming useless to buy used gadgets if you will later on need to replace it in just span of few time. Also ask how the users guarantee that the gadget will work properly and what are the terms in case something went wrong.