When I first started selling on Ebay I spent hours doing Internet searches to find wholesalers for my products.  Buried in all those results, many which were totally irrelevant or turned out to be retailers, I found a few real sources. 

I realized that I was totally dependent on two sources, with no backup; also shipging was really cutting into my profits.  I decided to look for local sources that I could use for backup.

I sell fossil and rock collections by buying items in bulk and assembling into a collection.  There are two rock shops in my area and I approached them.  "Do you sell to reseller?" I asked.  "Why yes we do." Was the reply (One offers 30% off store price, the other does 20%).  These were small businesses that've been around for over 20 years- my online suppliers have been around for 10 years or less.  Now I have backup!

Trilobites cost me $ 3.00 plus shipping from my online resources.  I can buy the same type, same quality at the rock shop for $ 3.00, NO shipping.  Don't approach large chains or multiple store operations; ask smaller LOCAL stores.