Yes, you can for under 50$
A mosfet could be described as a electronic device that handle the power delivery instead of you trigger contacts. You still need the contacts, but the will only handle the signal, and not the current.
You can get fairly cheap (in price, not quality) from Stealth at
AirsoftStore.ca. to install them, there are guides everywhere, and all you need is a solder base.
I installed mine from no experience and it works great. There's a link on my sig.