Fuel Injection - explain this to me like I am 6 years old

Got to be careful when spending money to increase gas mileage. A lot of the time its cheaper just buy the extra gas.

Id be lucky if I can drive my car 40 weeks out of the year. And even if i spend a $100 a week in gas and save 10% by going efi it will take me 10 years to break even more likely 15 years. I bought rhe holley sniper and fuel tank etc... $4000 Canadian so far. Still have to install it.

I mainly bought it for driveability reasons