I have six Ikea Tradfri USB Signal Repeaters available for sale for $30 (for all 6) + shipping. I don't have the power supplies for these anymore, but any USB adapter that supports 5V, 1A works.
This is a great way to get a strong zigbee mesh going. I have seen a single repeater connect to as many as 14 zigbee sleepy end-devices. The repeaters are relatively small and work well with Hubitat; there's a built-in driver for them.
Full disclosure: I'm selling them because I replaced them with TuYa zigbee repeaters, which are even smaller, and seem to work better with zigbee2mqtt.
