If there is a particular snack that you like and you would like to buy them back home, you can always purchase them in bulk from Makro. This is what I have done before when I was visiting Thailand as a tourist and would like to buy snacks home.
My recommendation is for you to walk into 7 Eleven to buy and try out whatever snacks that catches your fancy as they have small packs of various varieties sold individually. After you determined the brand and flavour you like, then head to Makro hypermarket to purchase in bulk.
This post I will focus on the Pocky snack because a number of people seemed to like this snack a lot. Pocky originated from Ezaki Glico company from Japan. I grew up being used Pocky as Rocky. In Europe, it is sold as Mikado brand.
If you go to Makro, you can see Pocky of all flavours sold in bulk at a much more cheaper price in Makro:
Pocky alternatives (similar but different brand):
You can also check out other brands that offer the similar snack.
Even though I mentioned Pocky, other type of snacks like Lays, biscuits and instant noddles are also available in bulk in Makro. However you would need to take note of the following:
1. Makro does not provide plastic bags or bags to store your purchases. Usually the locals would buy in bulk and push the items via a trolley to their cars. You would need to bring your own shopping bag to store your items if you are not coming with your own transport.
2. Makro is generally located out of public transport routes or train lines. Usually we go there using our own transport.
It is more common to see BigC at times along public transport routes. You can actually go to BigC too as they also have a section where items are available in bulk but their selection as not as extensive as Makro but usually the common brands would be available.