In Spanish, I'd say "me importa un pepino" ("I care a cucumber") shares as much popularity as "me importa un pimiento" ("I care a pepper"). Personally I've hear

In Spanish, I'd say "me importa un pepino" ("I care a cucumber") shares as much popularity as "me importa un pimiento" ("I care a pepper"). Personally I've heard/used the second one a lot more, but I guess it may depend on the region or something. But there are other, more explicit, expressions equally popular. There is "me importa una mierda" ("I care a shit"), and the most vulgar one is probably "me suda la polla" ("it makes my dick sweat") or, for short, "me la suda".