The rest of the year, impulse shopping isn’t necessarily a good idea. But when the days start hurtling by in December, it’s time to abandon forethought. Spot a miniature rocking horse ($30 at CVS, 215 Park Ave. S., nr. 18th St.; 646-602-8237) that actually neighs and clops when you squeeze its ears? Buy it! And the same goes for the other cheap-and-clever drugstore gifts on the pages ahead.