Yo mama so poor, when I rang her doorbell, she said, "Ding!"
Yo Mama Doorbell
Explanation
Explain Bear
Alright, listen up, buttercup. This "yo mama" joke is all about how super broke yo mama is. Like, so poor she can't even afford a real doorbell. Instead, she gotta make the "ding" sound herself when someone rings the bell. Get it? She's the doorbell, and she's broke. Also, you are probably broke too.