I got one on ebay for $100.00. It is easy to access under the trunk floor. New is about $2000.00

 

Considering that a car payment will likely be closer to $2k / year at a very minimum, I'd move the reference point a bit higher than $1k / year as being acceptable. However, having said that, I have a 2002 (16 1/2 years old now) and over 130k miles on it. It has been one of the most reliable cars that I've owned. I have had to replace a few items and do service on a few items but nothing that has left me stranded. The closest to being left stranded has been the alternator going out or the battery dying but with even those I was able to get where I needed to be to make a decision on it.

I am realistic though, I realize that I have suspension work and other items in my future, though no hints of needing them right now. My engine mounts are in okay shape (barely starting to show cracks), so they will need to be replaced in a year or two.

All that to say, I'm still very comfortable keeping my car for the foreseeable future. This is the oldest car that I've ever owned and is approaching to be the longest that I've ever owned a car as I've now owned it for 12 1/2 years. But it is not the most mileage that I've ever put on a car either (that would be over 200k miles). OTOH, I'm still struggling a little with just how long I will feel comfortable keeping it as my daily driver.

To answer your question as to how much that translates to, that would be difficult to answer. Ignoring tires, wipers, batteries, scheduled maintenance items and fluid changes, I've had many years with no maintenance. I've only had a few items that required repair: speakers, headunit CD player, alternator (once), 1 roof motor, trunk struts (twice) and a leak where the steering pump mounts. I don't think that I've ever spent much more than $1k in a year for maintenance, though the year that I had the roof motor replaced either came close or did go beyond. The cost will heavily depend on how much of the work that you are willing to do on it yourself also.

 

There have been several folks that replaced their amps by buying them on ebay like iolmaster indicated.

Regarding the speaker, there are a number of threads about folks that have replaced the speaker with other speakers and the controversy about using different impedance speakers (lots of discussion on that). But also, a lot of folks simply repair the speakers since the majority of the failures occur in the foam that attaches the speaker cone to the speaker frame. There are rebuild/repair kits that you can buy for about $25 (last I heard) and also places that you can send it off to that will rebuild them for fairly cheap. (Buying a new one from Lexus is crazy expensive.)