Legislatively, a commercial vendor is required to collect all exigible taxes, both provincial and federal. Therefore an Alberta vendor will apply the GST to the purchase price. There is no sales tax, yet, in Alberta. If the RV is delivered to you in BC by a division of the Alberta vendor you may then be liable for the BC sales tax. Take delivery in Alberta. For clarity the GST is equivalent to the VAT. In the event you wind up paying the BC sales tax, explore the possibility of having the sales tax refunded as a non-resident. This not a good comparison as it crosses the 49th parallel but, non-residents may apply to Washington State for a refund of state sales tax. The concept does exist.