When it comes to building backlinks for local SEO on a limited budget, there are several effective strategies you can implement. First, focus on acquiring local backlinks through a content-centric approach or by reaching out to local bloggers for links. Additionally, search for lists of donors or sponsors in your targeted city and collaborate with them for backlink opportunities. Lastly, aim for geo-targeted relevant backlinks and niche relevant links to help increase your page and website authority for better SEO rankings.