I purchased 2 pairs sp-2500 in really hice cosmetic shape for $80 a few months ago, and one set had replaced wooferers with rotting surrounds. I thought that was a great buy.
I would not hesitate to spend $50-75 ish on a pair that you describe. anything under 50 is a steal, over a 100 would be too much
heres what I paid for some sansui speakers within the last year..
sp-x9700 $200 minty
sp-x7700 130 minty
sp-x6700 60 cosmetic wear and one blown mid
sp-3700a $70 cosmetic wear but not too bad(was told all good, but found dead mids and a dead ambience horn..:thumbsdn:..try before you buy)
sp-2500 $80 for 2 pairs very clean cabs, but 2x bad woofer surrounds