Depends on if you are doing the work yourself or going to the dealership.
The price of the parts themselves are, for the most part, the same. You can go to a Lexus site, look up the part number and then see if an online Toyota dealership has it in their catalog. Most of the time they do. Even if it is a Lexus-only item, their prices are not much higher.
If you want a dealership to do the work, here in Kansas City, the Lexus service is considerably higher. An oil change at the biggest Toyota dealership is a little over $110 and at the Lexus dealership it is over $150. The difference in cost is going to be labor rate. Lexus dealerships have quite a bit higher rate than Toyota dealerships.