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 $4,478, a growth of 3972%.
Most valuable 2008 LEGO Batman set
7888 The Tumbler Joker's Ice Cream Surprise $1,437.33
Highest growth 2008 Batman set
7884 Batman's Buggy The Escape of Mr. Freeze +5747.85%
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 $584.20
Growth  +5747.8%
Annual growth 11.8%

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 $704.67
Growth  +3425.1%
Annual growth 12.4%

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 $754.00
Growth  +2414.2%
Annual growth 9.3%

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 $1,437.33
Growth  +2775.2%
Annual growth 10.5%

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 $997.67
Annual growth 11.3%