Setting Plaster is that lovely warm, dusty pink-beige that's launched a thousand bedrooms — and you can get within a whisker of it for less.
The pick of the bunch is COAT Out Of Office at ΔE 1.2 from the original (LRV 55.7). That's well under the threshold where the human eye notices a difference, so on the wall you genuinely won't clock it apart from Setting Plaster. COAT's a direct-to-consumer brand with sound eco credentials and a properly washable matt, so it's a strong shout if you want a true like-for-like at a friendlier price.
If you're after the cheapest route, Dulux Soft Almond 4 lands at ΔE 1.6 (LRV 51.8). Slightly less light than the F&B, but the colour itself is a cracking match and Dulux trade emulsion is everywhere — easy to get, easy to touch up. For a Setting Plaster look on a tight budget, this is the one.
Crown Reframed is the loosest of the three at ΔE 2.9 (LRV 53.3). That's still close, but at that distance you may notice it reads a touch differently in certain light, so I'd only go for it if you're already buying Crown for the rest of the job.
The honest caveat: a colour match isn't a finish match. Farrow & Ball's Estate Emulsion has a flat, chalky depth that the dupes don't fully replicate — part of what you pay F&B for is the way the surface eats light. COAT and Dulux both have a slightly more plasticky, durable matt, which frankly is more practical in a hallway or kids' room anyway.
My advice: order tester pots of Out Of Office and Soft Almond 4, paint big A2 patches, and live with them over a couple of days. North light will pull the pink out; warm evening light will push it peachy. Setting Plaster shifts a lot with the light, and so will any match.