You need like 10 - 15 green/purple white stones and also use red/blue for low upgrade:
Make from +0 to +6 with red or even +7 then use white + purple with 3 or 4 tries you might be +8 or even +9.
I spent around 3.4billion zeni without counting white stones from cash shop.
Guess you didn't get me if you're trying to teach me how to upgrade gear. Lmao. 3,4kkk / piece where a upgraded +11 is 1,5kkk - 2kkk from ppl. #Legitness. I used to spend 1kkk / piece to get my whole gear to +10-12 with a bit of luck. After these updates i spend 2kkk to get +6 dats all im sayin.
And p.s i not talking about weapon upgrades, i was talking about armor upgrades so why are you talking about weapon upgrades? ._.