Do it yourself and save yourself some money. Plenty of SEO guides out there for you to go over. Have a look on YouTube for video guides too.
Kudos to you for thinking of an original topic As for me, I stick with Google... can't go wrong there!
Some may say freelancer.com is a good for SEO Services. Infact, outsourcing your SEO can actually affect the efficiency and quality of your services. Quality SEO Services does not come cheap, unless you're willing to throw your money away for temporary rankings. You need lasting SEO, a campaign in which will drive traffic to your website that is targeted to your niche as well as opportunity to expand in the near future. This involves, link building, social bookmarking, blog commenting, url optimization, etc. Many factors go into SEO, if not done correctly, it can destroy your ranking in all search engines. You should really look into a firm, if you're not familiar to SEO.