This is a good place to go to for extensive array of mock meat/seafood products at wholesale prices. If you could not find any products, just approach the friendly staff or the boss there. They will help you and even give good recommendation.
Even if you don't really fancy mock meat stuff, there are other products like instant noodle, tibits, sauces, instant yong tau foo, different type of buns, heat-up food that might interest you.
The big bun (4 for $5), Lor Mai Kai, Fan Choy, Simple Food Vegetarian Baked Rice/Curry Baked Rice, Soon Kueh, Otah wrapped in Coconut Leaves and the Vegetarian Satay that comes with very flavourful Peanut Sauce and etc.