Slice Meat

The best cuts of meat for KBBQ
Beef
Kalbi/Short Ribs: These ribs are cut specifically for KBBQ, which are flanken cut short ribs, where the ribs are cut thin across the bone. You can also do boneless short ribs too, which are usually cut a bit thicker.
Bulgogi: Bulgogi actually refers to the sweet and savory marinade/sauce, not the cut of meat, but most commonly used are thinly cut slices of sirloin, ribeye, or brisket.
Bulgogi vs Kalbi
Even though they’re both beef, they’re not the same. The biggest difference is the cut of meat used. Bulgogi is made with thinly sliced meat and kalbi are short ribs. The marinade is essentially the same.
After H-Mart, most Asian grocery stores will have a selection of pre-sliced meats in the frozen section that are probably meant for hot pot but will work great for KBBQ.

And, finally, you can hit up the regular grocery store or a butcher. You can buy a rib-eye, pop it in the freezer and thinly slice it. Instead of Korean flanken-cut short ribs, get some boneless short ribs and slice those thin as well. Most grocery stores carry pork belly slices (sometimes called side pork) and chicken is always a good choice too, especially when you marinate it in the spicy bulgogi marinade.