The sure fire way to provide the accurate display of import/export rates when selling is to call customs to find out what tariffs will apply. You can either give them a call or search online.
There are always a number of things that affect the duty:
*origin of the goods
*manufacturing and trade agreements
If you are importing a large amount (e.g. by the container load), then you will need to employ a Customs Broker and/or Freight Forwarder to take care of your import for you.
Generally, most duty rates fall between 2% and 30%. Items like books usually have very low tariff, while shoes and clothing often attract some of the highest tariffs.
Dropshipping on the other hand is indeed a great way to get out of these customs duties :) Your rates, though will be slightly higher.
This is where you need to decide what is best for you - wholesale or dropship.
Hope this helps!