The cost is quite minimal. In many cases you are also able to keep your current SIM card as most phones now use the nano SIM size. Don't expect Koodo to ever stop charging for them. They like our money too much.
I think SIM cards should be provided for free with a new device, like Rogers/Fido do. You should only have to pay for them if you're doing a new BYOD activation or replacing your phone with a model not purchased from Koodo that requires a different size.