One neat thing is ancient Chinese coinage has a square hole in a round coin, I always thought that looked cool. Civilization is old in this part of the world, so there are tons of old coins. Song dynasty coins are about 50k VND locally (2.50). Want something older, from the Three Kingdoms period (over two millenia old)? That will be… the same price. They are so common that no one cares.
Ancient Vietnamese coins are a bit harder to find, and look pretty similar too. I have one of the first coins minted in the country, found it in some scrap metal recovered while dredging a river or a shipwreck or something. It’s worth… about 50 cents.
Great coins to collect for someone on a budget. Watch out for fakes – but they are pretty easy to spot.