Travel Thailan

If the question is about shopping while traveling in Thailand, specifically related to pet products, you might consider the Jatujak market.  It's definitely crowded there so I wouldn't plan a short visit but they sell lots of different things, including pet items.

We shop for different things when we travel than when here (I live in Bangkok), in some cases because selection is different, or pricing, but sometimes it just seems like we slip into shopping mode more.  Some things are easy to find here and relatively inexpensive, for others the selection is limited and import taxes make them more expensive than in lots of other places. 

I'd think pet supplies wouldn't be so different here than anywhere else related to price or selection, so unless you want something you're having trouble finding in HCMC it might not make sense, but the market is interesting if you're into such things.