kind of hard to write slang from any country, as u have a myriad. So im gonna write some colloquial words from Argentina.
First lets go on simple words, then expressions.
Taxi driver>>>Tachero A guy>>>chavon(most comon one) in northwest region chango is used, In the province of Cordoba they use Waso, and then u have the northeast which i think they say pascualito(not so sure about this one).
something that works or doesnt work, instead of funcionar, many ppl say Funca, example: mi compu no funca bien.
"una banda" means a lot. Example: Tengo que estudiar una banda!! garron, or bajon it's an unpleasant situation, example: u hear a conversation: 1- Perdí mi laburo chavon!! 2-que garrón!!!
"Me tomo el palo, or me tomo el buque" is used when u have to go, or leave a place u just say these ones, meaning that u r actually leaving.
"Corta la bocha" this is like "that's it"
and u have maaaany more, but guess i can't write them all, hahahah. Hope this has helped u.