Permanent buff upgrades?

I want to make a store that permanently upgrades buffs for example, Increase Fire rate, Projectile damage, etc, I tried… But for weeks I cannot figure out, Heres the code I was using,

This is to refresh the saved game and set the fire rate

And this is to purchase the upgrade so that it can be refreshed and used, Now I tried it and now I shoot like a minigun /: When I clearly set the delay to 1.0 So can anyone help?