Each slot cost increases $25K more each time you buy a slot.
There are 8 rows of 5 slots each, which makes it 40 space for you to store your weapons, armors, ammo etc...
*The first row is for free
*2nd row $25K
*3rd $50K
*4th %75K
etc....

Altogether for buying all 7 rows of slot worth:
25,000+50,000+75,000+100,000+125,000+150,000+175,000
= $700,000
On the slots