Hi im new to this site and i just recently purchased a 07 mazda3 from a small dealership and i was only given one set of key also with one keyless entry remote to the car and was wondering if i can just go to the mazda dealership and purchase another spare remote or would i have to completely purchase a new alarm system for my car?

 

you can get another key, but they have to program it

 

For the remote:
You can purchase additional remotes and program them youself (up to three total remotes). All you need to have is a working key to program remotes. You'll also want your working remote as the process of programming a new one will invalidate any current ones unless you program them in at the same time.

For the key:
You can have up to eight total keys. Here's the clincher. If you have two working keys then you can program in additional keys yourself in about 15 seconds. If you only have one working key then the dealer will have to plug into your car's computer, clear the existing key codes and manually program new ones. This process takes about 45 minutes and most dealers will charge an hour's labor for it. I've seen price quotes from $50-150, though most people end up paying somewhere around $60-75 for it (plus the cost of a key). I'd recommend getting a key online vs. buying at the dealer because many dealers will overcharge for the actual key. I recommend to everyone to buy a third key so that in the event you lose one of them you still have two and can get a replacement key to program yourself.

Alternately some lock smiths can "clone" your single working key. Basically they'll make the RFID of the new key match the RFID of the working key. So you'll physically have two keys but the car will recognize each of them as the same key. So while you're still covered if you lose a key you can't program in additional keys.