When you have a small business, it is likely that you will not have a large budget to spend on your marketing! For clients with smaller budgets, there is still a great deal of marketing which can be done, either for free or for cheaper prices.
One of the biggest costs in SEO is that of building links. It is not always possible to get a free link on a good quality website, and sometimes deals need to be made! For those with not a lot of money to spend, it can be worth investigating free link options such as through social media to get started. Just by spreading the word about your site via your friends and family, you can end up reaching quite a crowd.
In terms of cheaper onsite SEO, there are several things you can do on your own if you have the confidence to try a few things out -first, make sure you have good headings on each page. There should be just one H1 heading on your page, with a few supporting H2 headings underneath. If your site has more than one H1 tag, you will not get good SEO benefits from any links you build!