If you're trying to get money, don't do any of Franklin's assassination missions.  After you complete the game, then do the assassination missions and put everything into whatever stock is going to increase.  Go to your house and sleep two to four times, then sell all of that stock for profit.   To do it with all three characters and get the most out of it, I'd recommend saving before doing the mission with Franklin, do the opening part of the mission, loading the  game, then buy the stock for everyone.  If you make a mistake and lose all your money, you still have that manual save to fall back on.

Unfortunately the stock system in the game is rigged.  Completely based on events that happen within the game.  So making any sort of money through stocks legitimately isn't going to happen.

I'm gonna do that...but sadly, I don't have online access right now, so I can't access the BAWSAQ. LCN is fine though ofcourse, but it sorta limits what I can do.

the LCN is virtually impossible to make money out of unless you cheat with saved game files.  they have a basic range that they fluctuate in, and its not the listed high/low and the chart doesnt mean anything.   It took alot of patience and a pen/paper  to track the 10 cheapest(smaller price lets you see much higher returns as 40 cents for a 3 dollar stock is way different than a 500 dollar one)    Ive heard the radio and the website offers tips but i havent had any luck with that.

The Bawsaq seems to be the place to make loads of cash outside the assasinations.   PIS and HAL are the 2 lowest by vast margin.   HAL was 75 cents a few days ago and now its at 7 bucks.   thats dam good return.   PIS got down to 3ish and is now charting back up. I got in around 3.7.   if either of these return to the starting value,  even at current prices you will have 500+ percent return.

The BAWSAQ updates hourly.   just did a few seconds ago and PIS continues to rise.  at about 5.5 now.

I was thinking the same, did you but the golf place?