Fake reproductions exist, and can be identified easily by the fact that the Beatles' faces and text is printed on the brush, rather than embossed like the originals. The printing is also a different color than the brush.
Originals were very scarce until the late 1970s, when a Tacoma, WA (USA) collector discovered several unopened cases of the brushes. They were offered at wholesale for $3-7.00 and retail at $10.00 each, and slowly sold out within a couple years. Today they are more uncommon and usually sell in the $50-$80 range (still sealed). The 39 cent versions are scarcer.