How to implement simultaneous calls to vk api from different users on the site?

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Hello! I am writing my service to work with Vkontakte. The service uses vk api. Vkontakte allows 3 requests per second. This is enough for one user. But I plan that more than one person will use the service. Prompt, how such simultaneous requests are implemented? I tried to use free proxies, but work with them is not stable. It turns out that the only way out is in the constant purchase of good proxies for each new user? Thank you!