My advice when it comes to buying likes or followers for any platform is don't.

Most of their algorithms are specifically designed (or getting there) to reward accounts with high engagement, not high follower counts.

You'd be better off sticking to the 4-1-1 guideline for social media to drive engagement -

- 4 things of value to your target audience (other articles, questions, quizzes, local businesses (best places to grab coffee, lunch, etc.), challenges (like a house-hunting picture challenge to share with your hashtag on IG for buyers), etc.
- 1 thing showing your hobbies, personality - the human behind the account.
- 1 ask/sales - This would be your listings, an open house, referral requests

You need to prove value and people will engage because they'll know you're the expert you are.

Social media is the best way for you guys to leverage your local expertise to your network in a way that Zillow cannot hope to touch.