The most common mistake is to think that the tones are, or can be arbitrarily assigned to words in Mandarin. I could try to equate tones in mandarin to intonation and stress in English, but it's just not the same. Tonal languages use tones as a critical component in word meaning, if the tone is wrong, it is not the same word, almost like the difference between "career" and "car ear" in English.
Of course, tones based on relative pitch, one person's first (or high) tone may be quite different from another's, people who speak certain dialects completely slaughter the standard tones, but that is less important than the fact that they use the same relative tones with consistency, and the same utterances have the same overall tonal "shape", so it is easy to guess at what they mean.
Toneless Mandarin, or Mandarin with incorrect tones, or randomly assigned tones might be semi-intelligible at times, but it would require great effort from the listener, who would quickly grow weary or impatient with the situation (imagine someone randomly assigning stress and intonation to English). Other times such speech would be completely incomprehensible nonsense.
As far as your request, you can listen to the following on this site:[1]. By copying and pasting the following text, you can hear Mrs. Lin here do the following:
??,????: Correctly pronounce this sentence meaning: "Hello, I am a student."
??,????: Hear her pronounce the same syllable groups, but with randomly assigned tones.
??,????: Hear her pronounce the same syllable groups, but all in the fourth tone.
Unfortunately I can't provide you with all the combinations, because not every group of syllables occurs in every tone in Mandarin. "Wo" for example does not occur in the second tone by itself, nor does "sheng".
With a simple, common phrase like this, it would be easy to guess at someone's meaning, in the same way that I could probably get away with "Hell, oh. Eye must you dent.“ (Hello, I'm a student.) But you can probably see how such an arrangement would quickly confuse and or irritate a native speaker.
Hope that answers your question!