USA, Canada / sending text message to canada from poland [9]

I have family in poland and was hoping they would be able to send me sms's. I have a polish sim card from sim plus, does anyone know if they will send the sms to my phone in canada will it cost a lot for them to do this? Will I be charged in canada for receiving this sms? Has anyone from poland visiting canada have experience with this situation. Thanks! I really want my family to be able to write me and not have to pay a lot to do so.