Arduino pro mini 3.3 V Version! 1,57 € -- alternative 328P: 1,36 € RFM 95 W 4,72 € Ublox NEO-6M GPS Module GY-GPS6MV2 NEO6MV2 6.19 € -- alternative ? 2,16 € Ein / Ausschalter 0,08 € Battery LiPo 3.7 V 1200 mAh 5,30 € -- alternative: 4,61 € 3D enclosure (Thingiverse) total costs as of today, cheapest variant: 1,36 + 4,72 + 2,16 + 0,08 + 4,61 = 12,93 € and some cables and board Antenna for base station: https://de.aliexpress.com/store/product/Glass-Fiber-Antenna-Gain-8dbm-Transmission-range-is-further-LoRa-Gateway-Antenna-with-433-470-868/2805180_32852314761.html