Where can I buy portable breastfeeding pillow?

Depends on how portable u want it to be. Every Babyfair sure got quite a number of nursing pillows - if u can wait for baby fair which almost every month will have one. Or buy online like pupsikstudio (see photo) Do note that most people don't use it that long - prob abt 4 months or earlier u will stop using already. I personally got the wonder pillow from pupsikstudio