Suggestion for good used Integ. Amp for $ 5-600?

Tube Choices are: (Trust me, you cant go wrong!)
1.) Sonic Frontiers SFC-1
2.) Union Research Simply 12
3.) Audio Research CA-50

Solid State Choices are:
1.) Marantz PM-17SA
2.) Denon PMA-200R
3.) Roksan Kandy

you cant go wrong with the following stuff!!! naim nait-3,
linn majik, primare a-20....all are fantastic!!!