If you own the name - ask enom
If you don't own the name - check Ahead.Tv (but don't take it as gospel)
If you don't own the name - ask the owner direct
If the name is available to register - enom will let you know the premium as you attempt to purchase the name.
The SIMPLEST way of working out if a name is a premium or not is to see who the registrar is. If a name is at GoDaddy or any registrar other than enom then it is NOT a premium. If it is a enomcentral - it MAY be.