My wife needs a replacement battery for her white 13" Mackbook - year & model unknown. It’s used for legacy software. The battery is an A1185. Newegg and Amazon have them but from outside sources.
I second OWC, and also you might try BatteriesPlus; they are insanely overpriced, but if you want a name brand (like Rayovac or Sony), they have them, and offer good solid warranties, and might be local to you.
Otherwise, a year ago, I bought this one (https://www.amazon.com/Replacement-Laptop-Battery-MacBook-MA561FE/dp/B01LL8LFEO) and so far, so good. I paid $40 then; it’s $30 today. Might be old stock; no way of knowing till you see the production date, and if its too old to be confident, you can use the liberal Prime return policy (verify it’s eligible first, though).