SEO, Link building, Google/Yahoo

Hello, I own a site that is unique and geared towards a specific industry in business. There are a few words and phrases that I would like to be listed in on the first page of Goggle/Yahoo. The keywords/phrases are not very competitive - they average from a few hundred to several thousand searches a month on Google. I would like this to be somewhat lasting and not remain there for a week then drop down in a month. This would involve some link building and whatever else goes into this... If you do a good job you would most likely get alot of repeat business from me. Presently my budget for this is $100 - $250. Please provide details like past experience, why you think you can do this etc... Thanks :)