Used stereo amp for $300.00 to drive Triangles?

Hi folk's,

Could anybody recommend some used amps for around $300.00.
I will be using a Rotel RSX 1055 as a pre amp, with Triangle Celius speakers. This system is for both serious stereo listening as well as home theater. I'm looking for some warmth. Some amp's I am considering are as follows:

Rotel RB981
Parasound HCA-1000
B&K ST-140
Belles 150

This purchase will have to last me for the forseeable future due to my three older teenagers! As such, my choices are pretty limited so I have to make the right choice now. Their are few to none possibilities in my area so I am forced to make a purchase sound unheard.

Any suggestions would be greatly appreciated!

Thank You!

Danny