They don't tend to.
Infinity had the free FCBD prologue (which was reprinted in #1 anyway(?) with #1 being $4.99)
Age Of Ultron had the free FCBD #0.1 (which was a reprint of Avengers #12.1 which was $2.99)
Avengers Vs X-Men #0 was $3.99
Fear Itself had Book Of The Skull which was $3.99
Siege had Siege:The Cabal which was $3.99