Power inverter?

Anyone use one of these, was thinking of picking one of for vehicle, in case I am in a pinch. Probably be minimal times I'd use it, but for $9.88....

Does it have enough power? No reviews on site yet.

http://www.homedepot.com/p/Commercial-E ... pDz39zTles

The inverter is only rated for 100W in continuous use. This is probably not enough to run your blower unit and is definitely not enough to handle the heating element of the humidifier. I am not familiar with the specific power requirements for just the blower on your S9 unit, but my Devilbiss travel unit requires 150W for just the blower.

Most machines seem to require at least 300 watts. My PR System One and my old RemStar M Series fall into that category.
The Resmed machines used to have a note on their web site saying that a modified sine wave inverter (like the one you asked about) can't be used and that a true sine wave unit is required. I haven't checked to see if that is still true.

In the motor home we live in during the winter in AZ (and lived in full time for ten years) I installed a 600 watt true sine inverter and it will handle both my CPAP and my wife's Resmed S9 CPAP.
We rarely use it for the CPAPs since we stay in RV parks with full hookups. The power would have to go off during the night for us to use it.