Tea with Florence is one of Little Greene's most loved colours — that soft, dusky teal-green that reads almost grey in low light and comes alive when the sun hits it. If you want the look for less, there are a couple of honest options.
The best of the bunch is Crown Button Box at ΔE 3, with an LRV of 20.1 — near-identical brightness to the original. ΔE 3 isn't a flawless match (under 1 is imperceptible, under 2.5 is very close), so you'll see a whisker of difference side by side, but on a finished wall nobody would ever clock it. Crown's Trade emulsion is solid, covers well and is a fraction of the Little Greene price.
Next is Dulux Teal Voyage at ΔE 3.5, LRV 20. Same brightness as Button Box, a touch further from the original tonally. Dulux is everywhere, easy to get colour-matched, and their Diamond Matt is genuinely tough if it's going somewhere that takes knocks.
I'd steer you away from COAT Adulting here — at ΔE 5.1 and LRV 16.2 it's a meaningfully darker, more saturated take. Lovely colour in its own right, but it's not really a dupe for Tea with Florence, so don't buy it expecting a match.
The honest caveat: nothing matches Little Greene's pigment depth exactly. Tea with Florence has that complex, slightly chalky drama that comes from generous pigment loading, and cheaper paints tend to flatten out a bit in flat light. If the room is north-facing or dim, that difference is more likely to show.
My advice — buy a tester of Crown Button Box first, paint two coats on a big bit of lining paper, and move it round the room across the day. If you're happy with it in your actual light, you've saved a good chunk of money. If it falls flat, that's your sign the original was worth it after all.