Might get a good response in the HTML / Programming section.
Don't you just hate people who speak abbreviation language to an unknown audience. Is it too difficult to spell Search Engine Optimisation?
Go to Google, read their spiel for webmasters and take note. Beyond that a good, well laid out website with decent content should not need expensive SEO which could potentially lead to rank evapouration or banning later on.
I'd avoid any SEO agency that treats SEO as a it's own separate entity.
Any good agency knows these days that successfully promoting a website can involve everything from "raw" SEO to social media, from website conversion optimisation and customer retention and re-marketing right through to more traditional forms of media PR.
A good SEO agency should be sitting down with you and looking at your businesses goals and working with you to help archive it.
I run a digital marketing company although my client list is full at the moment I'm happy to chat any time.
Popped you a trust mate, maybe you'll like them, maybe you wont!
Feel free to ask around if the brand is any good, do your own research and you'll see they've won many awards.