In 1991, LEGO released 3 Town Promotional sets, all of these sets have been retired. For that year, the total price of all retail sets cost $25, today those sets are valued around $2,274, a growth of 9001%.
Most valuable 1991 LEGO Town Promotional set
1774 Aircraft $1,482.28
3 sets

1772 Airport Container Truck

Theme / Subtheme Town / Promotional
Year 1991
Pieces / Minifigs 80 / 1
Availability Retired
1772 LEGO Airport Container Truck
promotional
Value $609.43
Annual growth 11.4%

1773 Airline Maintenance Vehicle with Trailer

Theme / Subtheme Town / Promotional
Year 1991
Pieces / Minifigs 109 / 1
Availability Retired
1773 LEGO Airline Maintenance Vehicle with Trailer
promotional
Value $182.65
Annual growth 8.2%

1774 Aircraft

Theme / Subtheme Town / Promotional
Year 1991
Pieces / Minifigs 137 / 2
Availability Retired
1774 LEGO Aircraft
Retail $24.99
Value $1,482.28
Growth  +5831.5%
Annual growth 12.8%