Holy, need your help!

[GoGoGroomer]

Just bought my first used Yaris. 2008 base sedan automatic with 98k. Love this little car. However it was purchased hastily and I didn't notice what I'm hoping isn't the end of my Yaris just as we are getting started. Rust on the passenger door and both bottom sides of the car. Is this possible to fix without major expense at a shop? Sorry I can't figure out why those pictures are upside down
They're not on my phone lol

[CB900F2]

my 2008 Silver sedan as the same rust issue on the front passenger door also on the inside .. same lower right corner... i tried to sand it and prime and paint, but the rust came back

[thebarber]

sand, acetone to clean, primer for metal, paint

[yangluchan]

First to do is see if car door leak hole are not plug
At bottom of car door
When rain the water go inside the door
And water go down leak hole

And stop the spread of rust
Then sand then Use rust inhibitors
Then prime and paint with spray can