You are only paying $8.50 for it.
It's hardly their most important package to deliver.
And you're buying it from another continent. It's got to be sent from whoever has it in China across that massive country to a shipping company, and then has to pass through customs, and then it has to sail across the Pacific Ocean, then go through customs in the US, then it has to be organised into delivery by the US, where it either has to be driven across a continent-sized country, or flown there.
And if it flies across the US to you, then it has to be picked up once again at an airport and re-organised again for delivery. And then it has to be delivered by a postman or courier company to your house.
You're paying a pittance for an unbelievable amount of travel and effort in organisaton.
I've waited 3-4 weeks for things to be sent from somewhere in the UK to get to me before.
There are entire states in the US bigger than the UK that it has to cross, let alone the Ocean and the rest of China.