So I was going to buy something from a webshop that was using secure-checkout-page.com to make the payment. I did enter all my details, checked the total price and clicked on the submit-button.
After I did send the order the total order-value changed and they added $30 to the shipping-cost without even telling me about it on the page before! Luckily I used a temporary virtual CC-number to make this payment so I could easily block the payment within seconds.
But stay away from secure-checkout-page.com unless you want to get scammed.