Adding ads to your blog without paying is possible if you join free ad networks or affiliate programs. You can start with Google AdSense if your blog meets their guidelines. Platforms like PropellerAds or Adsterra also accept smaller sites. These networks place ads on your blog and share revenue when users interact with them. Affiliate programs are another option. You promote products related to your niche and earn commissions on sales. You can use referral programs to get paid without upfront costs. Focus on creating quality content to attract traffic. More visitors will lead to better earnings from these free options.