When we say " I wonder where you get money all from" we mean we don't know how does someone earn money ?
Hi, it should be 'I wonder where he/she/they gets all his/her/their money from'.
It just means that it seems like that person has/spends a lot of money, but we are not sure how they have that money.
For example, "Tom has been on 4 holidays this year. I wonder where he gets all his money from. He's just a taxi driver."