Standard Ebooks has a nice PD edition of the George Long translation.[1] Also Elizabeth Carter’s translation of Epictetus’s The Enchiridion[2] and Aubrey Stewart’s translation of Seneca’s Dialogues.[3]
I surveyed a ton of translations a few years ago and found Maxwell Staniforth's to be the best balance between readability and fidelity to the original text. Older translations (as is typical of older translations of ancient works) tend to use needlessly "elevated" language, while a lot of newer ones seem to be convinced the Greek is even more simple and informal than it actually is, for whatever reason.
Best read for me - most powerful and readable imo. I’m sure there is a better academic/true-to-source read. I’ve read about 4 different translations and Hammond always stick with me - possibly because I read it first.
If you have the time/inclination and haven’t already I’d also suggest reading Epictetus and Seneca first.
NB: My favorite of all the available Aurelius translations so far is Martin Hammond (Penguin Classics)