Hey y'all I somewhat found this method, might've been posted or discovered before me but wanted to bring this back up. all you really need is like 20k but you can do it with alot more, I usually just do 30k. So basically you spend that all on GAP Packs (preferrably fast-rolling them by as soon as you buy the pack spam B (Xbox) or O (Playstation) so you don't get the animation. Then after that you take the silver's and exchange them all into low golds. After that you put all the golds into alternate defensive playbooks set. hear me out, if you pull Multiple D or 46 they around 15k+ (on pc at least). If you pull another playbook no worries! you can still sell it for like 3k. You sell all the PUP's (if its worth more than like 2k), all the elites, and all the playbooks and usually make a decent amount of money.
When I spend around 30k I end up making 20k profit (Average) but recently have been very lucky with my playbook pulls. if you dont pull the good playbooks you basically break even or make like 5k profit. but when you do pull 46 or Multiple D you make a pretty good amount of profit for cheap.
Hope this helps!