We've offered flat rate shipping for a decade... actually two tiers, then free over about $100 like many web sellers. Our products lend themselves to that scheme because they weigh roughly the same per dollar. We don't sell feather pillows and barbell sets.
We get many telephone orders and it's easy to say "shipping is a flat $9." That worked great years ago... even made a buck or two on average on each shipment. (sigh, yearning for 2002 again!)
I believe that web sellers should always strive for simplicity. Flat rate shipping is simple. But I also believe in turning a profit.
The landscape is changing as carrier rates rise and the expected free shipping level is fairly fixed around $100. Free shipping is starting to strangle us, even in an era of near-zero inflation.
A few competitors are going to "free with $129" or the like, and those tend to use a lot of coupon promotions.
Does this worry you? What are you doing to pass rising shipping costs (up about 5% this year) to the buyer?