Carb cleaning cost/ fuel addatives?

[Glaucus]

Has anyone used these at all or are they a waste of money?
Also how much(ball park)would a carb strip down and clean cost new jets if needed and tune up, if I just give them the bike? Xj900f.
It's not happy at low end just off Tickover.

 

[Glaucus]

I can DIY, allready have manual. Just cba, But if it's £200 not paying that. It's almost certainly going to need a clean.

 

[Glaucus]

The reason I think it needs a clean, is you should have seen the rust in the fuel tank and more scarily, the wrong side of the fillter all though ibviusly much smaller size particles. I do not know the history, but my guess is its been left standing ages and just a fast new brake fluid, air filter ect, to make it look better. When replacing the rear brake pads, even the bleed nipples where totally blocked up.