For me, the pricing here is not expensive. As you spend even more at sushi restaurant, they have value set on last page on their menu. You can check it out, mango pudding, fanta drink, edamame are included in the set.
You are right, not many sushi vegetarian restaurant in town. So far, I only went 3 restaurants. 1 is in Sunway Mentari Count, restaurant name called 香海. Another 1 in Kepong but closed. You can try Xiang Hai, different type of sushi.