I have about 5 or 6 different architectural progams at hand (including Punch Home Design Arch. Series), and I can vouch for the time it takes to simply learn to operate the software. You can spend hours and hours and HOURS on the learning curve, then achieve only the most rudimentary design plans. Heaven help you if you are trying to achieve something that's not a box shape, or has any peculiar angles or curves.
And I'm a computer software instructor! (You can decide to take that for what it's worth.)
Eventually, I've still found good old graph paper, a pencil and a gum eraser the most user-friendly tools for drawing a good plan (and WAY less expensive).