The plugin does not sanitize and escape some of its settings, allowing high privilege users such as admin to perform cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.
Proof of Concept
Put the following payload in the "Currency Symbol" settings: "><svg/onload=alert(/XSS/)>
Add New Product. Set the Currency that corresponds to the Currency Symbol set above, and fill a price greater than 0.
The XSS will be triggered when viewing the product