Hi @LA_GENT1 ,
I took a closer look at the DPD Integration app and it seems that it requires a DPD account in order to use the app. You can sign up for one on the DPD website and they have a page that outlines shipping costs in more detail.
In terms of buying DPD labels directly through Shopify, I do not have any example rates I can share. You can take a look at the estimated cost of a label when viewing an unfulfilled order and choosing DPD as your fulfilment option.
Looking at the other apps I recommended (ShipStation and Zenstores), it appears that both services offer carrier discounts when you opt to use them to ship your products. This means you might be able to get cheaper shipping rates when using these services rather than simply using your own DPD account. I’d suggest speaking with the developers of the apps to learn more; Shipstation have an email address (support@shipstation.com) and a phone number (1 (512) 485-4282) you can use to get in touch, as do Zenstores (support@zenstores.com / +44 (0)117 205 0604).