The end result is having to start all over in many cases.
You might be wondering about soil. My first planted aquarium was a dirted tank and if that's a term you are unfamiliar with, that totally fine, just skip this part :) Using soil in your aquarium is definitely an effective method for growing strong plants but it has a few drawbacks specifically for the beginner and why I wont recommend it. Changing up your plant locations once they have rooted can be a nightmare and a lot of work. I have received many emails from new fishkeepers complaining of a never ending brown tinge in there water due to not using an appropriate sand or gravel on top. The end result is having to start all over in many cases.  I think it is well worth the cost of an active substrate especially for your first tank. Save the soil for a future build.