Don't buy before you go. Universal adapters are available everywhere in Thailand and cost less than they do in the West. Thai plugs are either two pin ...sometimes flat, sometimes round ....or three pin.

Vacuum seal bags is a good idea but don't you need a vacuum cleaner to take out the air.

__________________
“Not all those who wander are lost.” Tolkien.
Life is not measured by the number of breaths we take, but by the moments that take our breath away.