In 2008, LEGO released 7 Power Functions sets across 2 subthemes, all of these sets have been retired. Subthemes for that year included Accessories and Technic. For that year, the total price of all retail sets cost $82, today those sets are valued around $279, a growth of 240%.
Most valuable 2008 LEGO Power Functions set
8293 Motor Set $106.10
Highest growth 2008 Power Functions set
8886 Extension Cable 20cm +438.80%
7 sets

8293 Motor Set

Theme / Subtheme Power Functions / Technic
Year 2008
Pieces 10
Availability Retired
8293 LEGO Power Functions Technic Motor Set
Retail $29.99
Value $106.10
Growth  +253.8%
Annual growth 10.0%

8881 Battery Box

Theme / Subtheme Power Functions / Accessories
Year 2008
Pieces 1
Availability Retired
8881 LEGO Power Functions Battery Box
Retail $6.99
Value $34.77
Growth  +397.4%
Annual growth 14.0%

8882 XL-Motor

Theme / Subtheme Power Functions / Accessories
Year 2008
Pieces 1
Availability Retired
8882 LEGO Power Functions XL-Motor
Retail $9.99
Value $40.08
Growth  +301.2%
Annual growth 11.4%

8883 M-Motor

Theme / Subtheme Power Functions / Accessories
Year 2008
Pieces 1
Availability Retired
8883 LEGO Power Functions M-Motor
Retail $7.49
Value $35.87
Growth  +378.9%
Annual growth 12.2%

8884 IR Receiver

Theme / Subtheme Power Functions / Accessories
Year 2008
Pieces 1
Availability Retired
8884 LEGO Power Functions IR Receiver
Retail $14.99
Value $23.81
Growth  +58.8%
Annual growth 3.3%

8885 IR Remote Control

Theme / Subtheme Power Functions / Accessories
Year 2008
Pieces 1
Availability Retired
8885 LEGO Power Functions IR Remote Control
Retail $9.49
Value $22.23
Growth  +134.2%
Annual growth 5.8%

8886 Extension Cable 20cm

Theme / Subtheme Power Functions / Accessories
Year 2008
Pieces 1
Availability Retired
8886 LEGO Power Functions Extension Cable 20cm
Retail $2.99
Value $16.11
Growth  +438.8%
Annual growth 12.9%