Barrington BRG102 Series Student Trombone
The BRG102 features a .500" bore for a quick response and good tone, plus an 8" yellow brass bell with outstanding resonance.

Bell: 8" yellow brass bell
Bore: .500"
Slide: Regular

I'm not sure if this trombone is any good, but for less than $100, I don't think you can go wrong for a student level horn...

 

Weril GG292L Gagliardi II Professional Bass Trombone Closeout The GG292L features a .562-inch bore with an independent double rotor design in Bb / F/ Gb / D plus 3 interchangable mouthpipes to customize the reponse of the instrument to the player. The GG292L also features a 9.5-inch gold brass bell and open wrap design for outstanding resonance and response.