Sonarworks is a combined analysis/correction software and not what you want to use purely for analysis.
Room EQ Wizard, aka REW, is free and powerful. All you need is a calibrated reference mic. If you don't own one, ones like the
UMIK-1 get the job done for $75 if you have an interface and cable already.
There are also iOS and Android-based software/hardware packages, but REW is basically the gold standard for consumer-level acoustic measurements.
There are basically two dimensions to room treatment that most people are concerned with - frequency and time. Sonarworks and other room-correction EQs work in the frequency domain, trying to compensate for the peaks and nulls at your listening position created by the standing waves in your room, but keep in mind that they can make other listening positions worse, sometimes much worse. It only measures in a few spots and tries to figure out how to help in the tonal unevenness of your room, but you might end up listening from another position where you had a peak rather than null at the measurement position or vice versa, and the compensation is now throwing gas on the fire of your room's issues.
They also can't do anything about the time domain, i.e. reverberations in your room. Only absorption, diffusion, and scattering can accomplish that.
By analyzing your room, you can figure out where its biggest problems lie, and you can figure out how you want to address them (in terms of time, effort, and money).
The coles notes version of acoustic treatment is that whatever room you have in your home is probably an acoustically "small" room that needs bass trapping, and probably has nasty flutter echoes from parallel hard surfaces. Placing broadband absorbers at the first reflection points of the side walls and ceiling (as a cloud) makes the most dramatic improvement in the temporal domain, and bass trapping makes the most dramatic improvement in the frequency domain.
Bass traps can either be velocity-dependent (e.g. thick absorbers) or pressure-dependent (e.g. tuned membranes, helmholtz resonators, and active bass traps). Velocity-dependent absorbers are by far the cheapest, and once you choose the right density of material, it's about having adequate depth +/- airspace behind them, and then about having enough surface area of the room covered to get the bass under control.
Since absorptive bass traps are also broadband absorbers, they act at higher frequencies as well, and can easily end up over-deadening the reverb time in the room, leading to an uncomfortably dead space. Using hard, thin membranes or scattering plates on the front-facing surfaces can help them reflect high frequencies, allowing you to cover a greater percentage of the room's surface area for adequate bass control without creating a problematically-dead response at higher frequencies.
But measuring your space arms you with info to help keep you from making common mistakes. Like, if you understand that you have a massive issue at 60Hz, and then you notice many foam wedges sold as "bass traps" only don't have any effect below 125Hz whatsoever, you'll realize that they're useless wastes of money, instead of throwing a few hundred bucks at them and getting frustrated that you can't hear any improvement.