I'm not sure if this count as an anime merchandise, but I have some collection of used Ragnarok Online vouchers, Ragnarok Online was pay to play in my country. Not really that much since I was only a poor school student and didn't have an internet in my house and only able to play online games in internet cafe, lol.
Some of them already started to worn out, lol.
Oh and I have some Ragnarok Online stickers and bookmark, but I left it in my parent's house(I moved to my sister's house in different city now).
I think until now I still not own an actual anime merchandise like poster, figma etc. since I'm kinda feel uneasy when someone, especially my family member see them.