In 2011, LEGO released 2 Seasonal Halloween sets, all of these sets have been retired. For that year, the total price of all retail sets cost $10, today those sets are valued around $21, a growth of 115%.
Most valuable 2011 LEGO Seasonal Halloween set
40020 Halloween Set $13.13
2 sets

40020 Halloween Set

Theme / Subtheme Seasonal / Halloween
Year 2011
Pieces 71
Availability Retired
40020 LEGO Halloween Set
Retail $4.99
Value $13.13
Growth  +163.1%
Annual growth 6.0%

40021 Spiders Set

Theme / Subtheme Seasonal / Halloween
Year 2011
Pieces 54
Availability Retired
40021 LEGO Halloween Spiders Set
Retail $4.99
Value $8.32
Growth  +66.7%
Annual growth 2.1%