Any suggestions for a training slippers for my toddler that I can also buy in most accessible stores in Manila?

Hi, Bhie! Adidas Kids has training shoes and sandals for kids. This one below costs P1295 (pricey I know, though it can be an investment if you buy the size a little larger than your tot's size now so he can use it for a longer time. No worries if it is not that fit because it has adjustable straps). You can check it online at : http://shop.adidas.com.ph/akwah-9-sandals-kdp48.html?a=214_47481

Aside from Adidas, Nike has also an almost similar style for their training sandals. But I've seen non-slip training shoes/slippers perfect for toddlers from Toys R Us, it's called Attipas and costs around P999. Hope this is the same as what you're looking for in training slippers. :)

Landmark baby section has lots of slippers fit for babies with 5c sizes and up.