Hi Artur,
The suppliers we have in the directory that carry running shoes are mostly based in the US. If you are interested in taking a look at them, let me know. I also found a couple of other sites outside of SaleHoo that could be worth checking out. Please note we haven't verified these just yet (I have added to our internal list) but I wanted to try and get you a comprehensive selection, hope you don't mind :)
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Make sure you contact them directly in order to get their true wholesale pricing which is always better than you will see on their site. When doing this, provide them with the quantity you are ideally looking for, where you want them shipped to, and how often you plan on purchasing - this helps gets the best possible price.
Hope this helps! Let me know if you need further assistance.