In 2008, LEGO released 5 Batman sets, all of these sets have been retired. For that year, the total price of all retail sets cost $110, today those sets are valued around $3,937, a growth of 3480%.
Most valuable 2008 LEGO Batman set
7888 The Tumbler Joker's Ice Cream Surprise $1,165.47
Highest growth 2008 Batman set
7884 Batman's Buggy The Escape of Mr. Freeze +5003.20%
5 sets

7884 Batman's Buggy The Escape of Mr. Freeze

Theme Batman
Year 2008
Pieces / Minifigs 76 / 2
Availability Retired
7884 LEGO Batman's Buggy The Escape of Mr. Freeze
Retail $9.99
Value $509.81
Growth  +5003.2%
Annual growth 11.0%

7885 Robin's Scuba Jet Attack of The Penguin

Theme Batman
Year 2008
Pieces / Minifigs 207 / 2
Availability Retired
7885 LEGO Batman Robin's Scuba Jet Attack of The Penguin
Retail $19.99
Value $721.26
Growth  +3508.1%
Annual growth 12.5%

7886 The Batcycle Harley Quinn's Hammer Truck

Theme Batman
Year 2008
Pieces / Minifigs 267 / 2
Availability Retired
7886 LEGO Batman The Batcycle Harley Quinn's Hammer Truck
Retail $29.99
Value $655.97
Growth  +2087.3%
Annual growth 8.9%

7888 The Tumbler Joker's Ice Cream Surprise

Theme Batman
Year 2008
Pieces / Minifigs 449 / 3
Availability Retired
7888 LEGO Batman The Tumbler Joker's Ice Cream Surprise
Retail $49.99
Value $1,165.47
Growth  +2231.4%
Annual growth 9.8%

San Diego Comic-Con 2008 Batman and Joker

Theme Batman
Year 2008
Pieces / Minifigs 9 / 2
Availability Retired
LEGO San Diego Comic-Con 2008 Batman and Joker
promotional
Value $884.59
Annual growth 10.8%