Oishii Bento offers Korean and Japanese offerings, I have only sampled the Korean dishes.
Cheap, delicious, and fast. There is nothing else one can really ask for. I've sampled their Spicy Pork Bulgogi Bento/Bowl and their Galbi Bento, and both are delicious. All the meat options are made to order. Bowls come with the dish on top of rice while Bentos also include pickled yellow radish, kyoza's (Korean fried dumplings), japchae, and the choice of a basic salad (iceberg) with peanut sauce or kimchi. An entire meal runs for around $10 tops, and the average wait is definitely less than 10 minutes.
Highly recommended.