Best affordable seo agency for my small business

Hi everyone, this is my first time posting here.

I am running a small business and it's been going pretty good so far. I am running it with my business partner, and we finally decided to hire an SEO agency. Our current budget, realistically speaking is 200usd/mo, which may not be a lot, but we want to get something started. Hopefully it's enough to hire a good consultant.

So, what is the best way to look for one online?

Also, is there an agent that can do all the SEO? I keep seeing lots of adverts online."