Welcome to Basenotes, Hal!
That Amazon listing is sold by BeautyEncounter-- which has a good reputation here.
How long a bottle lasts depends on how many bottles one owns and how much one sprays on. If 50 ml lasted you over a year, worn daily, and you only had that one bottle, then I would say you are a light user!
Luckyscent does carry a lot of niche fragrances, which tend to be more expensive than designer fragrances.