He's still pretty young at only 300g and not a proven breeder so I wouldn't expect more than $300-350 like others have said.

On a side note, I have been offered $1300 for my almost 4 year old 1600+ gram female high white pied but she is unproven. If she was proven, I was told I could get $1600 for her. I would never sell her though as I'm weird and since I've had all my snakes since they were little baby worms, they seem like my 'kids' lol.