Roshi: So, how bout loaning your little brother some cash?
Baba: You still haven't paid back the last money you borrowed. 10 zenny isn't much but with 30 years interest I could buy myself a new crystal ball!
Roshi: Darn, I was hoping you would have forgotten about that.
Krilin: Master Roshi, since you and Baba are related, maybe you could put in a good word for us so she could tell us our fortune without any more fighting!
Bulma: That's right, families help each other out.
Baba: Are you kidding me? For family I charge double!
The manga (Japanese comic) actually portrayed the Invisible Man fight a bit differently. After Baba's singing ruins Yamcha's plan. Krillin had Goku fetch Bulma and Roshi. He then had Roshi stand in front of Bulma (with Bulma facing him) and tilt his head up. Then... lifted Bulma's shirt up revealing her boobs! Roshi, seeing this and being perverted, squirts out a nosebleed which lands right on the Invisible Man allowing Yamcha to see him and take him down.
In the original Japanese version, Bulma's boobs are actually seen for under a second when Krillin pulls her top down. That bit, however, was cut from the scene in the Blue Water dub.