You don't want to buy!!! Unless you hire a firm strictly for link building there are a lot of things you can do without having to buy links. This kind of falls under ( https://support.google.com/webmasters/answer/66356?hl=en ) Link Schemes.

If you're trying to rank local, Check out my recent blog for some cheap ideas: https://www.linkedin.com/pulse/top-2-gorilla-marketing-tips-has-seo-benefits-cost-zero-alonso/

National ideas could be

• Student or military discounts
• Resource pages
• Evergreen content with data that can earn media
• PR release of new Services/Products

Be consistent, Create Relationships, Be creative. Link building is difficult but doable. As a result, you will get create better opportunities.