Seeking Used Stringing Machine

I'm in the market for a used mid-level stringing machine that's in good shape for personal/at home use.  Would spend up to $500+/- for the right one.    

My only requirement is that the stringer have a fixed clamp system.  Otherwise, I'm open to various tension/mounting systems.  

Examples of the type of stringer I'm looking for from a quality perspective are:

• Alpha Pioneer DC Plus
• Alpha Revo 4000
• Gamma Progression ST II

If you have a stringer you'd be interested in selling please email me at brd2287@gmail.com and include the brand/model/condition info.  

Thanks, 

Brian