There is no need to have different colors among the positive tiles.  The positive tiles could all be of one color.  The negative tiles should all be red.  The tile sets are packaged in sandwich bags and enough sets are prepared so that each student in the class has his/her own set.  ( I also produced an "enlarged" tile set with magnets on the back for demonstrations at the blackboard. Magnetic strips can be found in any craft department. )

     Many of the commercial versions of algebra tiles are made from plastic and possess a "projectile" quality.  I have found that the homemade tiles are seldom "airborne" since they are aerodynamically deficient. : )

*Hint: When making your tile sets, consider asking for assistance from other adults, retired persons, younger children, and student helpers.  My retired mother ("grandma") was most willing to assist in making these manipulatives.

Template for homemade tiles for algebra: