I used to get electronic parts from Radio Shack. A blister pack of 4 or 5 small signal transistors was about $6. Radio Shack is gone here and I use Amazon for cheap electronics. A 200 pack of 2N2222 transistors was about $6. I need 4, and a few for the parts bin.
Happy to send a handful to anyone free. A bunch should go for a first class stamp.
Working on a 2 transistor logic inverter for RailPro to Bachmann Optical Chuff. Don uses a simple resistor, but I suspect the chuff pulse it’s not square as it should be. The inverter should fix that. I can’t really hear the difference, so it might be a waste of time, but it’s fun!