The Exchange Customer Pricing Add-on allows you to create variable pricing and/or allows your customer to enter the price they'd like to pay.
Once you've installed and enabled the Customer Pricing Add-on, go to Exchange > Add-ons and click the gear symbol next to the Customer Pricing add-on.
In the settings, you'll be able to change "or more" text that displays with on the store page with the price and the "Name your price" Label.
To enable this option on your products, you'll go to the Advanced options section for your product.
When you check the box for Enable customer price options for this product, you'll have the option to start adding the prices for the product.
Along with your price, you can give that price option a title.
Once you've added your prices, you'll see that one of the prices you added has a green check mark to the right of price.
This price will be the one selected by default. To select a different price as your default, click the grey check mark.
Below the Pricing Options, you'll see the option to Let customers name their own price. If you select this option, you can add a minimum and a maximum price that your customer can enter.
You do not have to set Price Options if you only want your customer to enter their own value.