I received my 2004 Lexus ES330 in 2018 from an inheritance. I love it! She has been good to me. Haven't had to do anything major as far as mechanical. Had to buy a new battery and alternator, besides that, just regular maintenance.
I recently converted my HID headlights to LED. I am not sure if it was a pain because I didn't know what I was doing, or if it is normally difficult to do. New caliper covers tires and wheels, a Kenwood aftermarket double-pin stereo system with Alpine amps and accessories, new black headlight assemblies, and all LED lighting throughout the interior.
That is about it:
Alternator: $150
Battery: $240 (Optima)
Caliper Covers: $250
Sound System: $1800
LED Headlight Conversion: $300
Wheels and Tires: $2500
Headlight Assemblies $300
Not too bad