Where can I buy a small cooler bag for under $20? Most places sell it for like $50-60

Yes, Daiso has $2 cooler bag. You can put ice cubes in a sandwich bag and make it cooler. Alternatively, you can get cooling panels from Daiso too. Place the cooling panels in freezer for few hours before place in the cooler bag.

Fairprice is selling for about $5. Daiso for about $2. You can also buy preloved at Carousell.

thanks