Virwox.com is one of the few services that accepts PayPal , Paysafecard etc... and that's why they gained a good amount of customers. also , I know It depends on the buyers but there should be a price range (something estimated, even If it's not accurate)
I think you sold your price for a good rates. I never trade in virwox and never buy sold the account. but I saw some offers and some asking requst to buy sell these and the price range was 50 to 100$..
Virwox.com don't even have an API as far as I know so building an estimator without collecting your login information's at least would be impossible and no I'm not , I'm just looking for someone who could give me the price range from experience (If he sold them or bought them already on the forums or somewhere else).
There isn't much data to collect anyways as the only factor is the level of the account