I bought a Duralast 130W inverter and it says 260 peak watts and it plugs into the 12V cigarette lighter. I want to charge my HP laptop with it. Is it bad for the car?
Your 12V socket is designed to deliver 12V, at a current described in your car manual. Most of my 12V sockets in the car can deliver up to 5A apparently (haven't tested this though, but I run a 200W invertor when I go car-camping. It is handy for everything)
The worst that can happen is if your invertor tries to draw more than the 12V socket is fused for - in which case the fuse for it will blow.
And as @Paulster pointed out in comment, you could drain your battery without realising it if you use the inverter with the engine off.
Nope. 130 watts at 12 Volts will draw 10-11 Amps of current. My ciggy lighter (Auto power socket) was rated for 10A of draw and has a 10 Amp slowblow fuse in it.
Depending on the load you might have problems if you run something inductive like a motor, rather than a capacitive load like a laptop. Items like blenders, circular saws, and so on are not good for an inverter.
Electric kettles and toasters are also a bad idea, mostly because of the load they pull (1000-3500 watts)
As long as your wiring and fuse are 10A or higher and the devices are appropriate, you'll be fine. If the fuse goes, the socket will be dead. If your wiring is substandard then it could melt and short the car's battery, but this could happen with any big load. Don't just replace the fuse with a higher-rated one if it does blow.
Others point out the risk of a flat battery, but also be aware that over-discharging a Lead Acid battery can make it sad. A 12V car battery should never be discharged below 10.5V, so set your car motor idling if you're using the inverter for a long time, or use batteries that are already old and cranky. 12V 7AH alarm batteries cost around $30 each and can work well.
Nobody has mentioned the load of a charging laptop. My laptop has a 19V 2.1A power supply meaning the maximum power in the worst case is approximately 40 watts. At 12 volts, this means about 3.3 amperes of current draw. However, your inverter might not be 100% efficient, so this amperage draw might be somewhat larger but probably not above 4 amperes.
According to Wikipedia, a cigarette lighter draws around 10 amperes of current. Thus, you probably have no problem operating an inverter in the cigarette lighter receptable in your car. Just make sure not to use it when the engine is off or else you may have a flat battery and may require a jump start. At max 4 amperes of current, you should have the ability to charge the laptop battery for more than 10 hours, because conventional car starter batteries are above 40 ampere hours. However, an old battery might have a much lower capacity, so I would not take risks.
Just to make it sure, you can take a look at the fuse box in your car. See what the fuse rating is for the cigarette ligher fuse. I believe the fuse is either 10A or 15A.