amazon sells a kindle version for ~$6. looks like deadtree copies retail under $10 online (or ~$17 from PRH). IA has it but it's covered under their stupid pseudo-library false scarcity bargain so you might have to get in line. if you're okay with physical, i bet your local library has it.
otherwise... can't check from work, but perhaps anna's archive/slsk has you covered?
https://openlibrary.org/works/OL1161327W/R%C3%A9flexions_sur...