The 10% off any first purchase promo code at the top of this page is the one to use if you are new to Natura Market and want a straightforward saving on your first order, it applies to all orders and you still get free shipping if your basket is CA$59 or more.
If you are placing a small first order, use the 10% off promo code. It reduces the total immediately and works across the site, so on a CA$40 first purchase you save CA$4 and still pay normal shipping unless you reach the CA$59 free shipping threshold.
If most of what you want is on sale, skip the code and buy the sale items. For sale items marked down up to 85% the site discount will beat the 10% code, on a CA$100 basket made up entirely of items at 85% off, the sale takes CA$85 off (final price CA$15) compared with a CA$10 saving from the 10% code.
If you want the free gift, spend CA$100 or more and take the free gift when your cart reaches that threshold. That deal is the clear choice when the free gift matters more than a small percentage saving.