In 1996, LEGO released 2 Primo sets, all of these sets have been retired.
Most valuable 1996 LEGO Primo set
2005 Duplo Primo $44.34
2 sets

2005 Duplo Primo

Theme Primo
Year 1996
Pieces / Minifigs 17 / 1
Availability Retired
2005 LEGO Duplo Primo
Retail $12.99
Value $44.34
Growth  +241.3%
Annual growth 3.7%

2078 Mini Set

Theme Primo
Year 1996
Pieces 4
Availability Retired
2078 LEGO Primo Mini Set
Value $16.45