getting an extra copy of key for my prius c 2015

IF......the FOB must be present for the car to start.....then you DO need a spare FOB too because if you lose the last one it will cost you about TWICE the $400 to get your car to run again and you will have no options.

Call around to some local locksmiths.
If they can do it, the price will be about half what the dealer wants.

 

Have NO idea.
If it is stamped into the metal key, my guess is that it refers to the key blank.
But that is just a guess.

 

Mine also says "H". I now wonder if all of them will say "H". This is the kind of key/fob I have:

 

You need to go to the Toyota Owners website. Put your VIN# in and see if your car has Toyota's anti-theft device installed. (Pretty sure it's standard equipment). If it does, then be sure to get a chipped key.

Welcome to Toyota Owners

Oh my key also has "H" stamped on it in case everyone else may be wondering.

 

I think the G or H just tells the dealer which kind of chip is in the key. Either way, everyone else is correct, you will be needing to go to the dealer to get it programmed. The chip inside the key is RFID so it needs to be programmed.

Although I've never done it, you could try a local locksmith and ask whether or not they can program a key for you. No idea how much but I wouldn't leave before verifying it will work every time.

When I got a second key from Richmond Toyota (I see you're in Surrey), they had to pull out their laptop and plug it into the car to program the new key.

 

Car Key Express made my non Smart key remote for $150. Apparently they are the subcontractor for the Toyota dealers. I bought the 3-yr warranty just in case.