Is there a way to find if the site is using shared hosting hosting or not?
You can try using a reverse IP lookup and see how many other websites run on the same IP:
Something like: http://www.yougetsignal.com/tools/web-sites-on-web-server/
Not necessarily with any surety.
You can do some poking around to figure out what host a site is using, its IP and even what server that resolves to(eg. web152.example.com), but beyond that, you'd need specific knowledge about the host to know whether that particular server setup was shared, VPS, etc. The obvious exception is if it ends up at a host that only does one type of hosting, of course.