said by extelus :

a billion? not likely.... the towers are already there... wave propagation in the correct format for HSPA requires what? a software upgrade perhaps,? some hardware outlay...but over time, and thats where the baseline of GSM propagates, the cost will be offset easily. Especially in handset costs, or lack thereof.

see the cbc website post above ...the projected cost is in the under half a billion costs for a Telus/Bell venture into HSPA.