Developing Health App to get data from wearable sensors

Hi guys,

I am working in Health app for android to get data from sensors of a smartwatch/smartband however I don't know what smartband or smartwatch should I buy to get conectivity with my app and test it. I am looking for a cheap solution just to test and with good sensors. I am reading about Google APIS that are easy to integrate with Wear OS, however I would like to know your opinion.

Thank you very much.