Nicholas J. Michalak said:

Why Boba Fett is lurking around the palace in ROTJ? Not sure. Maybe Jabba put him on the payroll as protection, but Fett's an expensive professional. From whom would Jabba be afraid of coming after him in his own palace to employ Boba Fett at such a high cost. I'm sure the Hutt's got the money, but that's not the point. Fett's not the type to just hang around out of luxury.

-NJM

I feel sometimes I come off as a "Fett-hater" but there's nothing in the movies to imply Boba is anything special that would be high cost. He's one of many bounty hunters Vader contacted to go after Solo. Fett was just on his game that day.

And there's also nothing to say Fett wouldn't much rather hang out in Jabba's opium den all day and flirt with dancers rather than gallivant around the galaxy in his uncomfortable little spaceship. Looks like a good gig.