You cannot serve G-d and Satan at the same time. You will either prefer sin while claiming to live for G-d, or you will hold on to your sinful lifestyle while openly despising G-d.
You cannot serve both G-d and money. This does not mean that G-d wants you to be poor, or not have nice things. It means you need to put G-d first in your life. One way you can put Him first is by tithing (giving a percentage of your income) to your home congregation/synagogue/church.
No one can serve two masters. Either you will *hate the one and love the other, or you will be devoted to the one and despise the other. You cannot serve both God and money.
*The word hate here signifies to love less in the original Greek.