There will be some extra money 
if you buy bitcoin and leave it to your favorite exchange then you'll get the same amount of bitcoin you invest. Bitcoin will remain the same and it will spike up for sure.
If you are actually planning to make an extra income make sure that you must keep your bitcoin in your own wallet rather than keeping it in exchanges ,always make sure that you are safe on that aspect and no further troubles if you spending some time to secure the coins in your own wallet rather than saving it online. if you buy bitcoin and leave it to your favorite exchange then you'll get the same amount of bitcoin you invest. Bitcoin will remain the same and it will spike up for sure.