P0021 p0011 p0024 codes check engine light on

So today I was driving on the freeway the check
engine light started flashing than turned off I
hooked a NOD scanner and no codes just say
misfire for all cylinders after that drove again on
freeway CEL flashed than stayed on. Now all the
codes for each cylinder misfire are on also codes
p0011 p0021 p0024 I have read up on a lot and
some says oil change some says replace camshaft
sensors (but how many are there ) also says spark
plugs and coils change. I don't wanna waste a ton
of money. What should I do what part should I
replace for these codes.