These are super cheep or free risers, but they do take se time

Step 1: What You Need

1 old bike inner tube X-acto knife Scissors Screw driver

Step 2: Cut the Inner Tube Part 1

Cut the inner tube so it's one long pice, then cut it in half so it's not a tube any more

Step 3: Take Off Trucks/ Cut Inner Tube Part 2

Take off your trucks and place them on the inner tube, use an xacto knife to cut along the edges. Do this for however many layers you want, I did 4. Cut little slits where the bolts go, then slide it on (you have to push kind of hard) do this for all the layers until its as thick as you want.