About four years ago we helped 3 aspirant companies to build sites to link to drop-shippers.
Of the three, two companies linked to just a single (quite large) drop-shipper here in the UK. (If you PM me I will tell you what that dropshipper is).
The third company went down a similar route to the one you are about to follow.
Today, of the three sites we built the two that are still in business are the ones that used a SINGLE dropshipper. These two are barely profitable, however..
The one that failed tried to use several dropshippers.
When we asked the client why the site had failed, he said that the practicalities of trying to manage all the activities of three different shippers was not only a nightmare (refunds, returns, enquiries etc) that erroded all his profits, but that most people abandoned their carts when they saw how expensive the shipping would be.
He also said that for the few customers who did order, he never got any repeat businss from them. Their purchases were just one-offs...
One of the other things that emerged was the wafer-thin margins you can put on top of your drop-shipper's prices.
Remember, a drop-shipper will have MANY people tapping into their system. Some have HUNDREDS of people selling via their own websites - some even have THOUSANDS of sellers.
Every one of these people is selling EXACTLY the same product, from EXACTLY the same dropshipper.
In this environment there is only one real differential... PRICE.
So, if you are buying an item from a drop-shipper for £10, you can be absolutely certain that there are scores of other sites selling that item at a fraction more than £10 just to be competitive (just look on Google Shopping to see what I mean!)
Our take on the drop-shipping industry is that it is now way beyond saturation point and is well past its peak. Unless you have massive resources, time and investment muscle, there is little point in entering the fray. Google Shopping has completely levelled the playing field. And PRICE is the only differential.
If you want to make money out of drop-shipping, then examine the potential of being the supplier (the drop-shipper). It's safer (in our opinion), than trying to compete as an agent for a drop-shipper.