Free or flat shipping shown in product page based on sales price [closed]

I’d like to show ‘free shipping’ or ‘shipping cost €7’ behind price in product page of woocommerce. It should be based on sale price. If sale price is > 100 it will show ‘FREE SHIPPING’, if < 99,99 it will show ‘Shipping cost: €7’
Someone can help me?
I think it could be a some if/else code to insert in function.php but I don’t know how to do it