This plugin let you add keywords to Virtuemart product page titles (to 'title' tag). You can add city name or word "buy" or anything else.
Search engines very love this shit. You can modify titles for all product pages or only in selected category.
Also you can remove category name from product titles or make it capitalized, for example.
VM product page title without plugin: "Tools: Big Shovel"
VM product page title with plugin: "Buy Big Shovel in New York for 10$"
In that case template will be: Buy %t in New York for %p$
Install and enable plugin. Go to plugin settings and edit page title template as you wish. Product title - %t and product price - %p.