Toyota Camry 2000 Problems

With a limited budget like yours I would suggest to go for a car with a good reliability record. While the Mercedes-Benz is a good car you are likely to be facing an expensive repair if anything should go wrong. Consider a Mitsubishi 380 or a Toyota Camry of around 2000-2003.

From your description it would seem that the battery is not the problem, and because the light is flashing on and off, I would be looking for a loose connection.
 

The recommended tyre pressures are detailed in your owner’s manual, and they are also shown on a sticker on the driver’s door pillar.

Buying at auction means you take on the risk with a purchase. That's why it's always best to go auction shopping with an expert on the mechanical front.

The Camry Hybrid is a very good car that gets The Tick from me. On the battery front, companies don't talk about the cost because they are expected to last for the life of the car and they generally provide assistance if there are dramas. I know of Toyota Prius taxis in Queensland that have covered more than 350,000km on the original battery.

There’s something wrong with your car to be so far away from the claimed fuel consumption figures. It needs to be checked by a mechanic with diagnostic equipment. I could be a problem with the oxygen sensor making it too rich.