Hi everyone (1st post). I'm looking for a inexpensive power mosfet for testing and for projects. The purpose is to control medium to large loads such as motors. An example is a project I'm working on now, where I need to switch a cars ignition coil on and off using a 555 timer to make a pulse jet igniter. I have also been experimenting using windsheild wiper motors for robots, and need a suitable fet to do this. I know I haven't given much info, but I just need something in my parts draw for these types of applications.
Driving an ignition coil and switching a motor are different enough that I would want to use different parts or at least different switching circuits. An ignition coil in particular is a good place for a MOSFET to drive a bipolar cascode switch although in that case the MOSFETs could be similar.
Looking to make a bulk order of both N-channel and the P-channel equivalent.
MOSFETs do not have complementary pairs to the extent that bipolar transistors do. For a given voltage and die size which determines the wattage and gate charge, the P-channel MOSFET will have a significantly higher drain to source resistance and lower current rating. For equal drain to source resistance, voltage, and current ratings, the N-Channel MOSFET will have a smaller die size yielding lower wattage and lower gate charge.
So for linear applications I pick MOSFET complementary pairs by matching their power rating as a proxy for die size. In switching applications where rated power dissipation is usually irrelevant, I pick them based on voltage and current.
As far as finding a low cost generic part, I would just search Mouser or Digi-Key or similar for P-Channel devices in TO-220 packages and sort by price and then look for the N-Channel part matched by power for analog and current for switching.