Used in informal settings, like chatting with friends or casual discussions about purchases. I wouldn't spend good money on trendy clothes; they go out of style too fast.
Pro Tip 2/3
Expectation of Quality
Implies the speaker expects something to be of high quality because a lot was paid. This laptop should last; I spent good money on it.
Pro Tip 3/3
Not Wasteful
Suggests careful spending on worthwhile items or experiences, not impulse buys. Investing in education is spending good money for your future.