Hi Rob, welcome to the forum. The coin you have is i think a copper 2pence, the grade looks to be a VF (very fine) or maybe a little better, but i'm not sure from the pictures, is there green spots on it as this could be Virdignis or copper disease. The rim is a little worse for wear around the coin, also bear in mind you're asking a dealer how much it's worth to him, but 50p sounds harsh to me.