Wordpress / Elementor / Ninjaforms - Challenge: If else / sales calculation

i’m looking for a soloution for the following problem. It’s a small form to calulate the cost of a product.

The form has only one field to enter: “Quantity” The Price of the product ist always $50. But the shipping costs are: For 1 piece: $10 From: 2-10 pieces: $20 from 11-30 pieces: $40

One way i thought: classic excel style with if/else statements the other way: a precalculated amount for every possible ordered amount. But both are not possible with ninja forms, or are they?

Or are ther any other possible ways?

Thanks!