The ESP Guitar Company

There's not a big difference between the two guitars, really. The pickups are a bit higher output on the Viper 50, but otherwise they're pretty much the same specs. If you're just starting, find the one that feels better to you (if you have a chance to play both) or the one that's a better price.

If they're about the same in both regards, pick the cooler color.

There from ebay the viper 50 is 120 for a red 1 the viper 10 is about 150 for black

When in doubt, pick the higher model number.

I have no experience with the Viper 10, but I bought a Viper 50 for my grandson for Christmas several years ago.  He has since decided to become a drummer so the Viper 50 is at my house and I play it from time to time.  For the money, it's well made with good electronics.  Without seeing the eBay listings to determine what issues (if any) there are between the two, if you can get the Viper 50 for a cheaper price, I would definitely go that route.