HELP INK FEFILL/S

hello! I'm looking for alternatives for ink refills and where I'm from (Tokyo, Japan) it is not that accessible for good brand inks like it is in NA/EU.

what I have in my area/web is only "Dope Liquid 200ML" for $16.50. I dont know if that's a good deal for it's price and size.

if there is any DIY, please do help a brother out and the specific paint/chemical that is accessible at any art stores, home center, etc. it will help me alot. thank you!