I use these: Board Game Pieces- 50 Pack- Blank 1 x 2 inches Rectangular Tombstone Diecut Token Cards with the Paizo Pawn bases. Just print the miniature on mailing labels and stick to the cardboard.

You could also use something like this: Game Board Markers - 12 Stands Plus 24 White Die Cut Cards if you don't have Paizo Pawns.