a K50 1.2 for 5,50 USD!!!... please link to that page... On the other hand there is no K50 2.0... but there's something strange about this for sure...
To the original question. The LX is, if functional, worth some 200€ almost regardless of cosmetic condition. You can check if the multifunction button (mirror lock-up, DOF preview etc.) is worn, that would indicate an older model LX that is supposedly more prone to sticky mirror. Though a newer model is by no means immune to it. A K50 1.2 goes for quite a lot in Europe,
HERE is a diagram showing prices in Germany, and prices in Germany are usually on the lower side.
Conclusion: If it all works it's a very good deal. If either one is not working you might want to skip it. But if you haven't shot with the LX I'd say that's a good enough reason to buy it.