There are several ways to do digital marketing without investing any money. Here are a few ideas:

1. Use social media platforms: Many social media platforms, such as Facebook, Instagram, and LinkedIn, have built-in tools that allow you to create and share content with your audience. You can use these platforms to reach out to potential customers and promote your products or services without spending any money.

2. Create and share valuable content: One of the most effective ways to promote your business is by creating and sharing valuable content, such as blog posts, videos, and infographics. This will help you attract and engage potential customers and establish your business as an authority in your industry.

3. Use email marketing: Email marketing is a powerful way to reach out to your audience and promote your products or services. You can use email marketing platforms, such as Mailchimp or Constant Contact, to create and send newsletters, promotional emails, and other types of marketing campaigns without spending any money.

4. Collaborate with other businesses: Partnering with other businesses can be a great way to promote your products or services without investing any money. You can collaborate on social media posts, cross-promote each other's products or services, or even host joint events or webinars.

5. Utilize SEO: Search engine optimization (SEO) is the practice of optimizing your website and content to rank higher in search engine results pages. By optimizing your website for relevant keywords, you can improve your visibility in search results and attract more potential customers to your website.