At moment mate it probably deosn't have any more value than reg fee but hold to it for a couple of years and see what the market says ? However it go like .tel and end up obsolete ? Good luck
I also have a 3L .co (WXE.co), I doubt it's worth anything more than reg fee right now, but just recently I see many people registering .co domain names and the last I heard most of the 3 L .co are gonna be all regged up. Might worth something soon, let's just wait for another year or something.
Not alot at the moment if you start to develop the site into say a short url site then over time it could well increase in value,a domain is only worth what someone is willing to pay for it not what the owner thinks its worth.