my remote key broke and l really want a new one..how much do they cost>>

Depending on the year you could be looking at around $400.
they are usually not cheap.
i would recommend calling your local lexus suppliers, they will give you a quote and order one up for you.

The price varies between models and year. They range from $75-$175. And it would cost $50 to program it to the car is computer.
You must go to the dealership in person with your license and the vehicle registration.
It takes a day to come in and 30 minutes to program.

Depending on key & type. The regular fob/key in one where u press lock/unlock & stuff is about $300 to replace. The ''Smartaccess'' fob where u do not need to remove the key is about $400. These r programmed & keys cut price.

You can go the E-bay route & purchase a key & get it cut at Lexus, but then u will pay more than if u purchased at Lexus, so it will probably even out.

3rd route is try Sewell Lexus Parts. just do google search & u will find out. They can program a key online with ur VIN, but u need to provide proof of ownership.

Good luck.