Write guest post
The cheapest way is to start by your friends who are on social media to help you comment on your post ,tag your business i their posts ,mention your business in their stories .Furthermore Instagram is seeing a threats from tiktok that is why Instagram introduced reels so this is a huge opportunity for a small business to be posting reels everyday so that it reaches more people .
In addition to that also having a good structure on your social media pages helps.
Advertise your business in a fun, yet informative way across multiple forms of social media, where it could then reach many people of interest
Starting a blog would definitely help you advertise your brand. I would also recommend joining an online community and contributing to growing it, therefore promoting your own brand at the same time.
By paying for ads of your business page on Instagram and other social media applications.