Here is equipment catalog of DEC. Mean prices is very approximate. It depends on seller: ebay, USA, England, Russia
equipment catalog
terminal & monitors / vt500 family
Model, P/N Item Mean price ~
VT510-A2 WHITE 149 $
VT510-A4 WHITE, 120/240V 169 $
VT510-A6 WHITE, LOW EMISSIONS 229 $
VT510-B2 GREEN 149 $
VT510-C2 AMBER 149 $
VT510-C4 AMBER 120/240V 169 $
VT510-C6 AMBER, LOW EMISSIONS 229 $
VT520-A2 WHITE 199 $
VT520-A4 WHITE 120/240V 199 $
VT520-A6 WHITE, LOW EMISSIONS 199 $
VT520-B2 GREEN 199 $
VT520-B4 GREEN 120/240V 199 $
VT520-B6 green 120/240V 399 $
VT520-C2 AMBER 199 $
VT520-C4 AMBER 120/240V 199 $
VT520-C6 AMBER, LOW EMISSIONS 199 $
VT525 MULTISESSION SYSTEM BOX 499 $
VT525-A6 MULTISESSION SYSTEM BOX 499 $
VT525-AA MULTISESSION SYSTEM BOX W/BASE 499 $