Most suppliers will provide different pricing to customers based on both 1. their relationship with the customer and 2. the size of the customer's order (among other things).
Just because a seller CAN purchase more inventory at a better price, doesn't mean they will always want to. If a product moves 100 units a month, they aren't going to buy 1,000 units and be stuck with inventory for 10 months. They are most likely going to purchase 100 units, just as you would. So even though they have more capital, they don't have much more buying power as they are most likely buying the same amount of units as you. Usually, sale volume constraints are more of a concern than available capital unless you are starting with very little capital.
Do I need to place large orders with suppliers to get good pricing?