I've been told someone in the know can be sure that his luck is asGood as gold, money in the bank, and you don't even pay for itIf you fold, a dollar in the shape of the pyramid that's printed on the back
There are a number of groups of three here. The three-syllable clauses or phrases "I've been told," "Good as gold," and "If you fold" are each set apart from the rest of the line because they rhyme with each other and because they're sung with longer note values (usually two quarter notes and a half note, in contrast to the multiple eighth notes that follow). Unique to the second verse, these three syllables are also three individual words, and, of course, there are also three lines in the verse (as I've formatted it, at least).
These various threes in the structure of the verses reflect the three sides of the pyramid, which is the theme of the song.