Here is the bill of materials for the 433Mhz Wemos Gateway, prices are from ebay US Sellers.
| Wemos D1 Mini | 7.85 |
| 400 Tie point (half) breadboard | 5.09 |
| 433Mhz Receiver | 5.15 |
| 2n7000 mosfet | 0.15 |
| 2x 10k Ohm Resistors | 0.08 |
| Random wires | – |
| Total | 18.32 |
If you are willing to go to a china seller, the total BOM drops to under $10.00
Even at $18.00 it is pretty reasonable.