I got my 2001 LS430 from a used car dealer, but came with a valet key only. I asked the dealer here, a new key with remote costs $380.
Can anyone suggest a cheaper solution please?? Many thanks...

 

local lock smith should be cheaper.

 

I got my 2001 ls 430 without master remote key, I only get valet and emergency card key, I get a used master key from ebay, for 68 dollars, make it work with the car by myself, so it starts to open close doors, then I cut a key for another 25, and I stuck with it, if you don't have master key you cant program immobilizer, so no engine start.
The cheapest price what I get from my local lock smith, was 250 for making my ebay key to start the engine.
But the end of the end, I make it work by myself, my card emergency key appeared to be a master chip on it, that helped me to program my remote key , as the another master, it starts the car no problem.