Shipping costs what it costs.
Canada Post is generally the cheapest system.
There are several posts by ypdc_dennis watching the current costs of shipping by SnapShip(Canada Post), Paypal , and the new Shippo!. All three have drawbacks.
In my opinion, using Calculated Shipping is your best bet, and I see you use that, followed by Free Shipping.
DON'T PANIC!
Free Shipping is just including a certain amount to cover your packaging and postage costs in the asking price for the garment.
Which is cheaper? A $14 blouse with $11 shipping or a $25 blouse with Free Shipping?
Which one sounds as if it were better quality? The $14 blouse or the $25 blouse? Smoke and mirrors.
Keeping down your costs is important too.
I shipped a tee yesterday, using one of the Free poly envelopes I got as part of my Store's quarterly coupon for shipping supplies. Specifically an eBay branded poly envelope. If it had been a woman's garment, I might have added some pretty white tissue paper and a cute sticker.
Between the discounts on labels and free to cheap packing materials, you can reduce your costs.
But if you want to continue using Calculated Shipping (which is probably your best bet) you could put those reductions into your asking prices.
Or just accept a little more profit.
But with your experience, you probably know all that.
Some sales are not worth having.
The buyer who starts out whining will never be satisfied.
