In 2003, LEGO released 2 Harry Potter sets in the subtheme Chamber of Secrets, all of these sets have been retired. For that year, the total price of all retail sets cost $30, today those sets are valued around $251, a growth of 737%.
Most valuable 2003 LEGO Harry Potter set
4720 Knockturn Alley $179.57
Most owned 2003 Harry Potter set
4719 Quality Quidditch Supplies
Theme / Subtheme Harry Potter / Chamber of Secrets
Year 2003
Pieces / Minifigs 120 / 1
Availability Retired
4719 LEGO Harry Potter Chamber of Secrets Quality Quidditch Supplies
Retail $9.99
Value $71.33
Growth  +614.0%
Annual growth 5.6%
Theme / Subtheme Harry Potter / Chamber of Secrets
Year 2003
Pieces / Minifigs 209 / 2
Availability Retired
4720 LEGO Harry Potter Chamber of Secrets Knockturn Alley
Retail $19.99
Value $179.57
Growth  +798.3%
Annual growth 7.4%