1. Does the plugin support arabic, hebrew, greek, cyrillic and other non-latin alphabets?
    Yes, it does.
  2. Is there any subscription based payment after the purchase?
    No. Once you get it, it is for lifetime using.
  3. Does the plugin display the prices after taxes?
    Yes, it is optional setting. You can include/exclude taxes from displayed prices in search box.
  4. Is it only frontend search solution? What happens after pressing an enter?
    Since 1.5.* the plugin can provide backend search results too.