There are a few ways to get $100 in free credit for Google Ads:

1. Sign up for a new account: Many times, when you sign up for a new Google Ads account, you will be given a credit as a promotional offer.
2. Check for promotions: Google Ads occasionally runs promotions where you can get a credit for signing up or for spending a certain amount on ads. You can check for these promotions on the Google Ads website or through Google’s partner sites.
3. Use a promo code: Some third-party websites and organizations offer promo codes that can be used to get a credit on Google Ads.
4. Take advantage of Google’s Non-profit program: If you are a Non-Profit organization, you can apply for Google Ads grants, which provide free advertising credit to help promote your cause.

It’s important to note that these promotions and credits may have certain restrictions or expiration dates, and it’s important to read the terms and conditions carefully before redeeming the credit. Also, the availability of these promotions may vary by region, and they may change over time.