Your $1.00 note nicely demonstrates an offset printing error. It is caused by another note (freshly printed) being placed & transferring its ink on the “error note.” Often each note is described (& valued) by collectors in terms of how much ink is actually offset (% of the side covered). I would say your note is probably about 15-20% offset & the more dramatic (up to 100% offset) the higher the value. All paper money errors are tough to rare (very uncommon) but yours will be slightly valued less due to the lower amount of area affected. Higher denominations also get higher premiums since less notes are printed, hence fewer errors are discovered.
Here is another link to some US offset errors posted on the Paper Money Forum (PMF). Unfortunately, its an old thread so scroll down to where some of the images remain. Here is another link to PMG's list of errors (note the 1985 $5.00).
Hope that helps!