If you want a bag, I would get a hanging bag. However, this depends on your ceiling. If this is a basement or room with exposed/able structure to hang a bag, hang it in the center. This will enable you to work the bag properly. It is possible to take down a 130lb bag by yourself, but putting it up requires help. Since you would be taking it down to grapple, you would have help at the ready.
There are obviously downsides to the hanging bag, and it may be impossible if you do not wish to mar the ceiling of a normal bedroom. That would require a freestanding bag or nothing, and I would probably just shadowbox "with power" (Bas voice), and use the money allocated for the bag to buy premium Thai pads, grappling mat, and just upgrade your essentials (wraps, bag gloves, training gloves, headgear, etc).
I have never seen a workable standing bag, especially for your circumstances. Most of them will tip over or move around your room with every strike. The best one I ever used was about 6' tall and allowed every strike, but the base was somewhat wide, which prevented tipping as well as hampering footwork. It probably weighed 300+, so mobility is even more of an issue than the hanging bag.
When you start making your choices for bag, gloves, mat, etc, post them on here before you purchase. It is highly likely that you will receive advice that will save you money and ensure you get good gear.
Also, as far as forums go, the Training Sub forums (Diet, Strength, Conditioning, Gear) are among the best on the internet in their respective categories. The percentage of knuckle-heads is low compared to knowledgeable, and if you get a consensus on something, it will be solid.