All wholesalers are not created equal. To be exact, there are wholesalers and there are wannabes. Unless you manufacture your own products, you are likely to buy from wholesalers. Many businesses call themselves wholesalers, yet they are ready to sell to the public. One of the tell tale signs of a wannabe wholesaler is that they sell directly to the public. You may do a search online for a wholesaler in your industry, but when you visit the site you find they are happy to sell to anyone. Wholesaling to such wannabes doesnt have anything to do with what you knew to mean wholesale; it simply shows their desire to sell a lot to as many people as they can.
A wholesaler with integrity will not sell to the public. Real wholesalers have an application process. They normally require resellers to sign up as a reseller. The application process includes a verification process such as faxing a business permit, or tax ID form to the wholesaler. Deal with real wholesalers, and ignore the wannabes.
Note: Wholesalers should never charge you to become a reseller. Remember, you are their customer. They have no legitimate reason to charge you a setup or initiation fee. If they try...