What is violent duct?
Survivals cost you a lot of ammo and take a lot of time. And honestly, there are missions that will give you more money per time you spend than survivals. So if you don't mind spamming them, they'll add up quicker.
Without a helicopter with missiles or a Hydra, I recommend Titan of a Job. It's a little long but it nets you 16 (if you are really quick to 22 or so if you take your time) and very easy to do on your own (it will of course get you more if you do with people but be much quicker). It's my easy money mission and if I consider it easy, that's saying something. I usually take a car that's good for cover and just snipe most the NPCs from a distance using my car for cover. Sedan like cars make the best cover cause they have two ends you can hide behind but get good shots when you need to poke out your head and aim. Super sports cars make shitty cover, they're too low. Then steal the plane and land it at Trevor's.
Buy at least a Buzzard (if you haven't gotten the Hydra yet. And yes, it is worth the 3 million dollars so save up. Most fun vehicle in the game). It will pay for itself in the long run, trust me.
With a buzzard/savage/Hydra (hydra will do these missions quicker but you get less money but if you don't mind it spamming over and over doing them quicker actually is more efficient at making money):
Trash Talk is a really good one (13k if you do it quick, 18k if you do it slowly. If you want to have fun exploding things great mission to waste time doing such as no cops will come)
Or Denial of Service (doesn't pay as much but still pays decently) <- disclaimer: I hate this one without a buzzard. I hate time limits and most of the trucks are easy until you get the one that has opposition around it.
With any helicopter you can call:
Cleaning the Cat house. Having a heli you can attack with might make it more fun but you don't even need that. Just land on the roof near where it says the NPC you need to rescue is and she'll walk up and get in the helicopter. Fly off. Land at Martin's. That's it. Decent money and super simple job with a heli.
You get another chance to customize your character
.