Dear friend, I will suggest that you can find the right suppliers from Amazon, Walmart, us.banggood etc..
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Have you tried Salehoo.com to see if they have good deals in their directory? They're supposed to have a full directory of 8000 wholesale/dropship suppliers of all kinds including athletic wear and all kinds of athletic goods and clothing and 25 million products. It's worth checking out.
We're thinking about giving them a try but want to get as much info as possible before trying. Even though they offer a 60 day money back guarantee, we're just being thorough. Please let me know if you have luck with them. Good luck and thanks,