Hello,
There's actually no demo as everything is explained through the product page :
Go in the menu HikaShop > Plugins
Click on the New button
Select HikaShop - Custom Field price in the list
Configure your plugin instance:
Choose the custom field you want to add fee depending the value.
Select the currency of the prices you will add
Add prices depending the custom field value.
Use the "+" button to add new prices
Set a default price for all other (non empty) values
But if you have any question, feel free to directly ask us.
We wish you a nice day !
Kind regards,
Mohamed Thelji.