Hello, where can you get money by doing coops?
I already kow 500 euro in '3 box' in Survival prison break.
Some told me 15k euro when got 20 boxes in survival??
Heard something about 20k euro when complete BG: begins Extreme???
Well, it seems to me like you only do CO-OP so to answer your questions the most well known method on earning euros is by in fact doing '3 boxes.' The 20 boxes in survival I wouldn't recommend because not only does that waste time I've never seen anyone actually get 15k from it. Battle Gear: Extreme does give you 20k on the first time of completion so I would try and do BG: Extreme! If I were you I would try and solo it because it's much easier than doing a 4 man team since they spawn more and are stronger. If you need help you can refer to this thread that I made. It's a step by step tutorial on how to beat BG: Extreme LEGITLY and earning you that EXP/SUPPLY to rank up and earn alot of euros!
It can be found here:
As for Lockdown at 1000 badges they give you 10k or 20k I forgot, but It's still euros. How I obtained it was by doing Lockdown extreme and I would try to go as far as I could. I would always die at round 10-12 so that means 10-12 badges I got. (1 Round=1 Badge) It's a long process, but it's worth it!
As for great alternatives you can do Demolition, Escort, or Annihilation as it gives a huge bunch of supply and exp (If played right)
I hope this helped you in anyway! Good Luck!