First time seller: help with average prices for shipping fees from China

Hi guys,

I'm about to list my first product but all the fees compared to how much I'm looking to sell it for are making the profits not even worth it.

So I'm ordering 150 units of my product for £5.41/unit, and the shipping cost from China to the UK is £485.57, each unit weighs around 1.48kg.

I'm listing the product on Amazon for £19.90 per unit as the regular selling price is around £21-£26.

The 150 units comes to £811.50 to buy and this combined with the shipping comes to £1,297.07.

If I sell the 150 units at £19.90, that will come to £2,985, Amazon FBA takes about 30% of this so that's down to £2,089.50.

So my potential profit is £2,089.50 - £1,297.07 = £792.43

And that's not taking into consideration tax

This seems very low. So my questions are:

Are my expectations too high? Am I not buying enough stock? Am I paying too much for shipping?

This is still a learning curve for me so any advice at all will be greatly appreciated.

Thanks