celtic and roman

Could you help me id this Metal Detecting Find or send me in a direction/website Where I can upload metal detecting finds and get answers easily

This is a Celtic spear found in the republic of Serbska 15 years ago,my father is found it buried in a field, as you can see in the picture, the spear is in excellent condition, no corrosion. I am interested in whether this has a financial value on the market and how much can be worth anyone...