There is more than one way to skin a cat, and certainly many ways to approach implementing necessary Search Engine Optimization (SEO) strategies. If you do not have a large budget, you can still benefit from SEO by using the techniques discussed in 3 Simple Ways to Build a Winning SEO Strategy on a Shoestring Budget by Chris Glarratana.
Remember, clearly define your goals first, and then hone in on long-tail keywords that will give you the most bang for your buck.
Best of Luck,
@Joywsimone