We recommend using either Kontakt.io or Estimote beacons for best performance and price. They both use the same chipset but package them differently. Kontakt.io beacons are plain and durable with a replaceable CC battery, while Estimote beacons are in a designer-made case and have a 3 year battery life. Beacon price depends on the number of beacons required and the features of the beacons, but are generally €20-€30 each.
For large installations, Locatify can provide beacons directly at partner pricing, and for indoor project testing purposes, we suggest: