Hi Simon,
Welcome to our site! :) Indeed, dropship suppliers vary in their requirements. Some impose a one time start up fee, and some, like the one you are wanting to use, require a minimum order amount. This is one of the dropshippers’ way to ensure that they are dealing with legitimate sellers. It does cost them time and resources to set up a dropshipping account and it will be a dent in their expenses if they accommodate too many ‘players’ just trying to have a taste.
You will also realize as you go on, that some drop shippers will be offering different pricing tiers, depending on how much sales you were able to bring in to their company. It is their way of ‘rewarding’ their performing clients.
And then with dropshipping, my personal opinion is that one should have a long term goal of eventually moving to acquire true wholesale merchandise. You cannot create as much profit margin with it as you can with buying in wholesale/bulk.
All the best!:)