My shipping is $35 flat, $20 flat if you are in Wisconsin, and free over $249.
Something to note, in the end, you are essentially paying the same amount for shipping from most vendors (except massive ones like live aquaria). The lower the rate, the more that cost is being added into coral prices, etc. The higher the rate the less you’re probably paying for the livestock. Free shipping is also factored into prices. So you’re really paying the full shipping price no matter what in most cases. So in the end I would pay little attention to shipping costs to be honest. I’d love to just charge actual shipping and lower my prices even more on coral, but most people require flat rate and free shipping.