You can do this at any of the many casinos found around New Vegas, including Freeside (suburb N of Vegas), the New Vegas strip and even Primm (once you find them a new sheriff and some time passes).
I'd advise betting the minimum (1 chip in Primm where I did this) since the odds are heavily stacked against you. After 10 pulls, the achievement will unlock, win or lose. On my game, the achievement took a few seconds to pop after my 10th pull.
Just like in the real world, slots are for suckers who like blinkenlights more than winning so it's tough to make money here. If you try to cheat using save/load the game will detect this and prevent you from playing casino games for about a minute.