Before jumping around to find a cheap SEO solution, I would suggest reading, reading and more reading about the current Search environment and what competitive companies are doing to improve and maintain their rankings. One suggestion, particularly with regards to marketing; look for quality and expect to pay for it. Like any investment, money well spent, is returned down the road in the form of profits. What's more, there are plenty of quality DIY options for Search Optimization, that won't cost you an arm and a leg. I'd suggest checking out Web CEO. Hope this helps.