Another good option for indoor signage and point of purchase is styrene.  Both PolyS and Styrene are susceptible to sun damage and discoloring, so they need to be indoor only.  Most Styrenes are one-side print only unless bleed-through is not an issue.

*Indoors only

*Medium durability

*Many thickness options and die-cuttable

*Any shape

*Normally 24 hour lead-time