The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

...but close to taco stands
and CHEAP prescription drugs...
The Big Bang Theory Season 1, Episode 12

You're just some
fucking CHEAP imitation.
Westworld Season 3, Episode 8

Oh, and don't CHEAP
out on the tip.
The Big Bang Theory Season 5, Episode 4

on a CHEAP monkey movie
The Big Bang Theory Season 7, Episode 17

I think I can put together
a CHEAP Swedish media center.
The Big Bang Theory Season 1, Episode 2