Cheap WIFI Internet

We want to purchase a Ring security system to protect a vacant rental that we're fixing up to sell, but there is no internet connection there, and we hope to only need one for a couple of months. We don't need TV, we don't need phone service, we just need the wifi internet connection that the Ring system requires. There is a good cellular signal there, if that can be used. What is the best solution available for us to do this? We're in the St. Louis, Mo. area. Thanks a lot for your help with this.