You can buy the blank key with the built in immobilizer chip and alarm function for about £40 and then it's £10-£20 to get this cut to you existing key. This will then unlock the doors and turn the engine over, but the engine will not start without the chip in the key being programmed into the immobilizer on the truck!!! Toyota will not do this without you owning the master key and or the key number plate. It may be possible to get a specialist firm to program the immobilizer to recognise your new eBay key, but they will need all of the keys you own in order to do this as the first step is to erase all key codes from the immobilizer, so they will need to program all of the keys back in. Not a bad thing if your missing the master key as if someone is wandering around with it then it will no longer start the truck. The other thing to bear in mind is that the erasing process may render the immobilizer dead!!! Not always, but occasionally! Leaving you then only with the £900 lock set option!! The chaps that do the re-programming do this mobile and charge about £125 + VAT. I know all of this as Swampy is missing the master key and key number plate, so only has one key at present and as a result I've invested some time on the phone to Toyota discussing my options with them and then on the phone to a local specialist auto lock smith firm. If anyone has an easier cheaper method that they know of please please let me know 
Because £200 for a spare key with a slim chance of then having to spend another £900 if this does not go well dosn't have me rushing to the cash point as a priority job 
If you don't have the master key and the key code then Toyota will not supply you with or program an additional key for the truck! They will however sell you a new lock set with ignition barrel a master key, a spare key and a valet key all the locks including the glove box and program them in for you for around £900
Did you have the little number plate with the master key or just the master key and did they ask you for all your keys to reprogram the new key in? It's a complete con the whole spare key thing from the main dealer!!! They only need the key code from what I can tell to get the new key cut. The programming part can be done without this code, so to my mind I should be able to walk into my local dealer with a key that I've bought from off of eBay and had cut at my local Cobblers with my reg doc, passport etc and have it programmed in, surely?!
It's easy to do yourself on an 80 and I think they used the same basic system for quite a few years, stick a master key in, turn it so many times, open and close the door so many times, stick the new key in, wait a minute, take key out, open and close door, job done. Slightly different sequence to erase all the other keys just shorter. In terms of this programming of the immobiliser ECU the designation of master key or not is purely how the ECU was programmed it is not determined by the keys themselves. From the factory the programming has all the black keys as masters and the grey ones are not but a PO could have bought a new black key and had it programmed as a sub key or a grey key and had it programmed in as a master for example. There are physical differences between the black and grey keys so that the grey won't open the glovebox but that doesn't determine its immobiliser ECU status. On an 80 if you poke a wire in the right hole and put your key in the ignition you can read a code to know if it is a master, sub or unrecognised key so the same thing probably exists for 90's.
