First, make sure you have installed Searchanise and Coin apps!
In the Searchanise control panel, go to the Integrations tab and tick the Enable Coin app support checkbox. Next, click the button Apply Changes.
After these steps, the prices in the Searchanise Full-Text Search widget will be converted according to the selected currency in the Coin widget. If the prices aren’t converted, then clear your cache and reload the page.