Not sure where you're at, but for staples like sesame oil, rice vinegar, rice wine, and condiments like chili garlic sauce, black bean paste, wasabi (powdered,) curry pastes, you can usually do a little better at the myriad of asian grocers scattered throughout Chicago. However, Mitsuwa is a cool store. good idea with thhe cooler. I'd suggest getting some sushi staples if you plan on trying it out - rice, nori, a bamboo mat, rice vinegar. Also some masago or tobiko if that floats your boat - it freezes pretty well. I'd also suggest, oddly enough...CANDY!
Their candy prices aren't the best, but they have quite a selection. Pocky sticks, and gummi candies. Asian gummies are really good. Check em out. Ice cream Mochi if you aer packing ice in your cooler (although it might not survive the ride for OTHER reasons.)
If you're gonna stock up on asian staples, some I'd suggest are GOOD oyster sauce, some ponzu, chili garlic sauce, sesame oil, chili oil, and anything that looks good in the condiment aisle. (kid in a candy store syndrome.)
We cannot be friends if you do not know the difference between Mayo and Miracle Whip.