Need woocommerce plugin for dynamic pricing based on sold quantity

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Hello everyone,

can anyone recommend a plugin/theme that can help me achieve such functionality:
http://www.shein.com/pre-sale.html?icn=preorder&ici=www_navbar02banner02

Basically first 20 buyers get $ price, other 20 buyers get $$ price, and other 20 buyers get $$$ price.

Thanks!