밑져야 본전이다: have nothing to lose, here goes nothing, trying wouldn’t hurt
밑지다: to lose
본전: an original cost, principal
~ 해야 (해봤자) ~ 이다: even though ~, it’s still
Ex) 공부해봐야 소용없다: Even if you study, it’s no good.
→ Even if you do a losing business, you’ll still be left with the initial amount of money.
→ You won’t make any profits out of what you invested, but you’ll get what’s worth of how much you invested.
→ You have nothing to lose.