What makes Japanese food so unique is it's taste. Certain ingredients cannot be substituted. Takoyaki uses dashi (cooking stock), shoyu (soy sauce), bonito flakes (fish flakes), and kewpie mayo. With this in mind, I've been going around different Japanese establishments trying out Takoyaki.
We've also tried the ones in Nihonbanshi Tei in Pasay Road. It's crispy on the outside and soft on the inside. The cheapest authentic ones that I can think of are the ones in New Hatchin Japanese Grocery in Makati. Here's the takoyaki area over at New Hatchin. An order takes about 20 minutes to make, but still worth the wait.