Buy as diluted as possible -- the more dilute, the less it oxidized. Buying a bottle to split down to smaller bottles and freezing can keep it going for a long long long time. I spoke with a few trusted vendors and everyone agrees that nicotine stored properly (and dividing up a big bottle into smaller bottles to reduce opening and closing effects on a batch) can go for years and years.

I use nude armor v2 and I don't even freeze it. I've had a bottle since December or so and it's still perfect. If you do freeze it I imagine it would last for a long long time

http://www.carolinaxtract.com/#!product/prd12/1907041705/1-liter-100mg-ml-nicotine-usp-pg-solution

I have gallons of 50 mg nic in my freezer that are fresh as the day I bought them. I use 50%pg for storage in 250 ml amber glass bottles with the poly cone cap.Fill it all the way to the top with no air. The liquid will contract when put into the freezer creating a vacuum seal.

I bought this and had excellent results with it. No harshness, yellowing, or having to freeze. I keep my nic in my basement near the concrete floor in a closet, in a brown paper bag with the rubber seal around the cap.

My nic came in a 120mL dropper (100PG) from Carolina Extract. (100% satisfaction) I haven't broken it down since I planned to go through it in about 6 months. If I ordered a larger quantity, I would definitely consider breaking it down and storing it in a freezer and keeping one working bottle.

EDIT: ordering 3 cans from this vendor is cheaper per unit than ordering 4. I know there are other vendors, but this is who I went through to get 1 can just to try.

Thanks for the answers everyone. I think I'm going to go with the nude armor and freeze what I'm not using. Hopefully I'll be able to use most of what I have stocked up now, and then make some more room for my next big order.

Still have ~100ml from my first order 3 years ago in the freezer. Still perfect last I checked on it in January.

Amber Glass + Argon + Diluted down to 50mg.

FWIW, you can buy argon in a spray can, specifically meant for spraying into containers to keep the contents fresh longer. It's called Bloxygen, and it runs about $9 a can IIRC. It was originally created to keep wood finishes from drying out or oxidizing in the container, but it works for anything. It's probably not quite as good as having something oxygen-purged in a lab, but it helps and it's cheap and easy to do yourself.

Various woodworking suppliers carry Bloxygen, but I've also seen it on Amazon. They probably have a list of dealers on their site too. Frankly, given Nude's less-than-stellar rep, it wouldn't surprise me if that's all they were using themselves.

ok, so everyone is suggesting ways to keep it fresh, and that is AWESOME. but what i dont see is anyone suggesting to you how to use older nic. You can test the nic for its strength. If kept bottled and frozen it isnt going to "Go bad" as much as it is going to go weak over time. The nic will oxidize, this is going to happen NO MATTER what you do. its just the nature of the universe. you cant get every single molecule of o2 out of there.. so there will be some degredation. I'd say to stick wtih all these ideas to keep it as fresh as possible, but also after a year or so invest in a test kit. Wizard labs sells one, it has no nictone in it, so you should be able to buy it no problem. Its just some acid and bromethyl blue that you do a titration test with (start wtih known quantity, add drops of blue, add acid till it turns yellow, do maths, get results).

Also - i dont think there is going to be a "border patrol" checking your car as you cross the state line, so you could always take a little road trip every few years to stock up..