make a quick buck

make a quick/fast buck (to earn money quickly, easily and often in a way that is not honest) — быстро заработать большую сумму (возможно, нечестным путем); срубить бабло (сл.);

EXAMPLE 1: Times are hard — you have to make a fast buck wherever and however you can. (CIDI)
EXAMPLE 2: They tried to make a fast buck on the property but they actually lost a lot of money.

see also
[зашибать деньги]