Notepad++ : How to find multiple instances of a string on the same line and replace the entire line with found strings

For example:

Suzy sells sea shells for USD$55 and USD$65 and USD$20 
Dave sells all kinds of junk for USD$30
Philip sells CDs for USD$40 and USD$10

Output needs to be:

55, 65, 20
30
40, 10

The Matching string USD appear on a line multiple times. Is there a way to make this work?

I’ve tried

search: ^.*?USD$([d*?]+).*$
replace: $1

Doesn’t give me ok results.