Two comments:
1) As has been said, both your laptop and your cell phone run on DC - simply find the proper voltage plugs and you're good to go from the cigarette lighter. Converting the power back to A/C and then back to D/C is needlessly expensive and clunky. Be careful though! Check the Voltage! Do not assume that 12vdc is 12vdc, and hard wire something expensive into your car's power, without noticing that inside that tiny cigarette lighter plug the voltage was getting reduced to 7.5vdc, or something else. That's a brief and expensive puff of smoke. DAMHIK. :drool:
2) It is useful to have an inverter - I hardwired a 750w max (400watt constant) inverter into the back of my 4runner. Not enough power to run hairdryers, irons or other implements of heat production (although I have used it to run a soldering iron). Most hairdryers require at least 1800 watts, and you're over the ROI threshold for me. Plus I like to discourage things like that on camping trips. But it's great for blenders, coffee grinders, pump for the air mattress, I've used it for drills (although they turn a bit slow - not going to work for big jobs) and when somebody in the rush to leave the house grabs the wrong charger for their phone, and then has a scheduled conference call mid way through the trip. Also DAMHIK.
I had to go through several, as many these days have an "always on" fan, and since mine is hardwired I would always hear it. The draw is so minimal that there's no danger to the battery, but the noise bothered me. So I found one by Husky at Home Depot - has been working like a charm for 6 or 7 years now. Need it maybe once a year, find excuses to use it much more than that.
I mounted it in the rear so it would be out of the elements. It's small and looks like an amp. I went up a gauge in wire size because of the length of the run, grounded it directly to the battery (per manufacturer's instructions) and wrapped both power and ground wires with this kind of hard tape - forget what it's called right now, but more durable than split loom.