Carolina Extracts COVG is excellent, top shelf nicotine. If don’t open the bottle, it will store in the freezer for many years without oxidizing - there is no oxygen exposed to the nicotine up to the point where the bottle reaches your hands. Their shipping is fast, but not cheap. Though it gets a little easier to accept when buying a few 120ml bottles, which come out cheaper than a similar volumed large bottle.
Here is a coupon code for 7% off: Dada1 (oddly that code is case sensitive)