I would be pretty careful paying someone to provide SEO services for you. Period.
I agree completely. You can certainly pay someone to set you up initially and give you some tips, but no way would I hire an agency for "ongoing SEO".
I talked with a few SEO companies and they all sound very similar. The price has varied from $500/month to $2400/month. Has anyone worked with a SEO company and what were your results?
Your site is going to rank based on your content and authority (backlinks, mentions, etc.)
If it really costs only 2k per month to do that, don't you think everyone would do it?
Because you really don't want to do this yourself, hire a full-time writer to produce your content, do backlink outreach, get you quoted, etc.
It's going to cost a lot more than 2k/mo but you're much more likely to see results.