Facebook ads as previously mentioned by other Realtors® is the best way as they can be run for a very low budget and lets you target the demographics you want.
Reverse prospecting will get other agents engaged which will contribute to a quick sale.
Nextdoor doesn't let you post for free, they require a monthly subscription.
Other social media such as Twitter and Instagram can be used to leverage the listing.
Best of luck with your new listing.
Abbas Naqvi
Realm Real Estate Professionals
24044 Cinco Village Center Blvd., Ste 150
Katy, TX 77494
Email cell: 281-235-4582