| From the introduction, each mask cost a different amount to purchase.
By clue 6, the four masks cost a total of $160.00, with the most expensive
selling for $64.00.  Neither the Gollum (clue 2) nor the Pennywise (4) mask
sold for the high of $64.00.  If the Freddy Krueger mask had cost $64.00,
by clue 3, Alex would have spent $32.00--by clue 5, the least any mask would
have cost.  Then the two masks together would have cost $96.00, leaving a
total of $64.00 to be spent on the other two (6).  However, since no two masks
cost the same, one of the remaining masks would have had to sell for
more than $32.00 and the other for less.  So, if the Freddy Krueger mask
were the most expensive, Alex couldn't have spent the least, contradicting
clue 5.  The Leatherface mask cost $64.00 to buy.  The Leatherface mask
isn't Luke's (1) or Alex's (5) choice.  If Sean had bought the Leatherface
mask for $64.00, the Pennywise mask would have cost $48.00 (4).  Then
the remaining $48.00 would have been split $40.00 on the Freddy Krueger
mask and $8.00 on Alex's choice (3).  However, given amounts spent of
$64.00, $48.00, $40.00, and $8.00, there would be no way for clue 2 to work.
Therefore, Chris bought the Leatherface mask for $64.00.  The Gollum mask
cost $32.00 (2).  By clue 3, Alex didn't pick the Freddy Krueger mask; nor
did he buy the Gollum mask, or the Freddy Krueger mask also would have
sold for $64.00.  Alex chose to go as Pennywise on Halloween.  Since the
Freddy Krueger mask and Alex's pick cost $64.00 between them (6), by clue 3,
the Freddy Krueger mask cost $48.00 and the Pennywise mask $16.00.  Sean
picked the Gollum mask (4).  Luke chose the Freddy Krueger mask.  In sum,
the four masks were purchased by the boys as follows:
 
 
-  Chris, Leatherface, $64.00  
 
 -  Luke, Freddy Krueger, $48.00 
 
 -  Sean, Gollum, $32.00 
 
 -  Alex, Pennywise, $16.00 
 
  
 |  
  |  
  
  |