There are eight flips to be preformed, all cost 15,000 credits excluding the starting two.
To preform a flip Ollie (press A/space) and then press the following button commands.
8 FLIPS (keyboard controls):
J = Kickflip (unlocked from the beginning)
K = Heelflip (unlocked from the beginning)
L = Shove-It
; = Impossible
M = 360 Flip
, = Laser Flip
. = Hardflip
/ = Inward Heelflip
Xbox controls:
Left and B = Kickflip (unlocked from the beginning)
Right and B = Heelflip (unlocked from the beginning)
Up and B = Shove-it
Down and B = Impossible
Bottom right and B = 360 Flip
Bottom left and B = Laser Flip
Top right and B = Hardflip
Top left and B = Inward Heelflip