Some basic notes about several of the transistors that I have played with:
For N-ch FETs, the Drain pin is usually pulled high through the load. Source often tied to ground.
For P-ch FETs, the Source pin is usually pulled high to VCC. Gate is pulled high to VCC, then taken low to turn on device. Drain pulled to ground through load.
Prices are from Digikey web site, as of 1/2/2017.
BJT's: