In 1969, LEGO released 2 Universal Building Set Supplemental sets, all of these sets have been retired. For that year, the total price of all retail sets cost $9, today those sets are valued around $332, a growth of 3801%.
Most valuable 1969 Universal Building Set Supplemental set
103 4.5V Motor Set with Rubber Tracks $166.13
Highest growth 1969 Universal Building Set Supplemental set
990-2 Trees and Signs +13136.80%
2 sets

103 4.5V Motor Set with Rubber Tracks

Theme / Subtheme Universal Building Set / Supplemental
Year 1969
Pieces 32
Availability Retired
103 LEGO 4.5V Motor Set with Rubber Tracks
Retail $7.25
Value $166.13
Growth  +2191.4%
Annual growth 5.7%

990-2 Trees and Signs

Theme / Subtheme Universal Building Set / Supplemental
Year 1969
Pieces 13
Availability Retired
990-2 LEGO Trees and Signs
Retail $1.25
Value $165.46
Growth  +13136.8%
Annual growth 5.8%