I'm going to be honest so take this for the constructive criticism that it is.     
Alone it's too simplistic for selling.   And you never sell the first model you make.  If you've just begun modeling, you need to practice, offer your practices up in the freestuff section and get some experience and feedback on your work.   
Also, from the images you show, it's not realistic in that it looks way too heavy to be held in the way it's being held.  The texture indicates metal which would make the thing heavy at that size.   Never sell something that isn't usable right out of the box, this means textured and accurately scaled.  Bonus additions for such an item would be smart-propped and possible hand/body poses to match.

Again, just my honest opinion and the best of luck.