In order to launch integration for price estimation it is necessary to launch script as:

node price_estimation_integration.js projectKey1 -price --10.25 -currency --CZK projectKey2 -price --250 -currency --USD

The order of projectKey, price and currency is important!
The provided example will be parsed as:
{
    projectKey1: {
        price: 10.25,
        currency: CZK
    },
    projectKey2: {
        price: 250,
        currency: USD
    }
}

"projectKey1, projectKey2" are values for the fields that are defined in the application as "Project key" field.
They are probably supposed to be identifiers of projects in JIRA.