Extra costs cause abandonments
Extra costs too high (shipping, tax, fees) is the #1 reason for cart abandonment, according to Baymard (source)
If your shipping is not free, you could offer something like this:
If you don’t get your product in 24 hours, we’ll pay for the shipping!
From members of my Ecom Convert group:
Typically that threshold is placed just above your average order size if AOV is low… otherwise it’s just high enough to prevent a loss on paid shipping. Threshold is dependent on your audience, products, and competitive market
From personal experience, I’d say that I often try to buy more stuff to get above the free shipping threshold. But if there is free shipping on the only item I want, I won’t buy anything else. However, I’d say that the nature of the item matters. For example, if it’s something that is an appliance or takes a long time to perish, I won’t mind buying more. If it’s something that perishes quickly or has few uses, I’ll try to find the site that gives me free shipping from the getgo. I’d say the 50-100$ range would make most sense.