(SM) It's like pepper. Get a jar of it and it lasts for ever. I had a girlfriend who was very keen on the said bitters whereas I preferred bitter. I had a sip of her drink once - it was vile.
[SM] Have you got a bottle of gin handy? Add a couple of dashes to a G & T and you get pink gin. Used to be very popular in the '60s when I used to work behind a bar.
Gin could be arranged, although it's not something I normally drink. But plainly I could buy a couple of crates of gin and the bitters would still outlast them. And a bottle of gin would lakst me 3-6 months. Y'know, I was viewing using up this bottle of bitters as a challenge, but unless I really go for it, which is sort of cheating, I don't think I'm going to manage it in my remaining lifespan.
Pink gin and water is also nice. 2 or 3 drops added to a ginger beer is one of my favourite very, very low alcohol drinks. Oh, and one of the several versions of rock shandy is 50/50 ginger ale and soda water, with a few drops of bitters. A bit of searching and I've found culinary uses at this site