once you've completed the Merryweather heist you will need to purchase the Sonar Dock Collection property (North west on the map).This does cost quite a bit, 250K to be precise, but the financial payback is worth the investment.
Purchasing the property unlocks two side missions. The first is the Nuclear waste collection mission, there are 30 barrels to be picked up, each worth $23,000 which means a payout of $690,000!
The second mission, a 'Freaks and Strangers' quest, involves you picking up the remains of a sunken submarine (30 pieces in all). Although the mission itself doesn't result in any cash payout, many of the locations you visit also happen to be the same as that of the hidden packages (not to mention a plethora of guns, body armour and health). I think its 10 out of the 12 hidden packages you'll find at these locations with a combined payout of 120,000 approximately.
Im not gonna lie, it took me a few hours to collect all this stuff but the profit made was totally worth it.
$560,000 if I'm not mistaken and that money if invested properly on the stock market using Lesters tips could easily turn into a few million. Hope this helps some of you guys
