If you have a vanilla opt-out your contract is tolled and you get a $150,000 advance on next season's salary.
If you have a high-risk opt-out your contract is tolled (but you still get an accrued/credited year for other purposes) and you get paid $350,000 (it's new cash, not an advance).
Either way, you do get paid any signing bonuses you contracted for even if there are no games at all this year.