coin, token, currency, mint 
[noun]
[de munt, de mun-ten]

"Munt" is the general word for "coin" and is also used for coin-shaped tokens; the ones that are typically used at festivals and in clubs. Naturally, small tokens become "muntjes". The place where coins are mint, is called "de munt".

And yes, when ordering mint tea in the Netherlands, ask for "muntthee"!

Examples:
– "Heb jij nog munten, dan haal ik effe bier." 
("Do you have any tokens left? I'll get us some beer." Note the colloquial "effe": even.")

– "Pardon meneer, u laat een munt vallen." 
("Excuse me sir, you've dropped a coin.")

– "Is de euro een sterke of een zwakke munt?" – "Weet ik veel, vraag het me morgen nog maar eens!" 
("So, is the euro a strong or weak currency?" – "What do I know, ask me again tomorrow will you!")

– "Ik vind die euro's maar niks; geef mij maar de oude 5-guldenmunt!" 
("I don't like those euros one bit; I'd rather have the former 5-guilder coin!")

– "Hebt u voor mij een muntje voor de sigarettenautomaat?" – "Ik weet het niet, u ziet er jonger uit dan 16!" – "Echt waar? Nou, dankuwel!!" 
("Can I have a token for the cigarette vending machine?" - "I don't know… you look younger than 16!" -"Really? Well, thank you!" Note that to buy cigarettes from a machine in the Netherlands, you typically need to get a token from the bar/counter which you shouldn't get if you are younger than 16.)

Expressions:
– "Iemand met gelijke munt terugbetalen": to give someone a taste of their own medicine (lit. to pay someone back with equal coin).
– "Munt slaan uit iets": to capitalize on something, to cash in on something.

Related words:
– Geld: money [noun] [het geld, de gelden]. Plural form only used for 'budget' or 'funds'.
– Wisselgeld: change [noun] [het wisselgeld, <no plural>].

Example:
– "Gepast betalen a.u.b.; deze automaat geeft geen wisselgeld terug."
("Please pay the exact amount; this machine does not return change.")

– Muntgeld: cash (in coins) [noun] [het muntgeld, <no plural>].
– Muntje: (small) token [noun] [het muntje, de muntjes].
– Munt(en)automaat: token dispenser [noun] [de automaat, de automaten].
– Uitmuntend: extraordinary, very good, excellent [adverb/adjective].
– Pepermunt: peppermint [noun] [de pepermunt, <no plural>].