Liquid nitrogen isn't that bad or dangerous of a substance. It's also very cheap. (Air is 75+% Nitrogen so it's very easy to compress air then distill it into nitrogen, oxygen, etc.) I used liquid nitrogen almost every day a few years ago when I was doing research. We used liquid nitrogen and solid acetone (Obtained by pouring acetone into liquid nitrogen) to cool off some reactions. The dewar flasks do a good job of keeping the nitrogen liquid. lol. But you can get a large amount (I'm talking multiple liters here) for less than a hundred bucks. I think at work a few weeks ago we ordered a large vat of the stuff for only 75 bucks. (This was a huge vat that probably holds forty or fifty gallons.)
Liquid nitrogen won't hurt you unless it contacts your skin for a long period of time. If you took some from a dewar and just poured it over your hand, it would probably boil off before it could do too much damage. (Although I'll admit, it does start to sting after a short period of time.) So the only problems with it are that it causes all of the water in the air around it to condense due to the intense cold, and if you don't have a well ventilated room a liquid N2 spill could asphyxiate you by replacing the oxygen in the air.