I just got an EKO Rio Grande 12 off of Ebay in good condition with original pegs, tuners etc. for £52.55. Of course, the nature of ebay means that i may have just been lucky, people not being at their computers at the end of the auction and so on. I've watched Rangers go for upwards of £150, and there was one for sale at Guitar Junction for well over £200.
If it plays well then somebody will buy it, but to pinpoint a figure would be difficult. Start at £150 and you might get lucky, but be prepared for a haggling sesh!
All the best and let us know if it sells