T&T and HMart both have Bonito Flakes and konbu at good prices and it is easy to make your own.
1 cup water. put in loonie size piece of konbu, bring to boil and add 1 handful of bonito flakes. Turn heat off and let sit for 10 to 20 mins. Strain.
Voila, Dashi. Works great for making tempura dip as well as soups and dressings.
After the 1st time you can adjust for personal taste of amount of bonito and konbu and make larger or smaller amounts of course.