A solid hitting infielder, Repp was drafted by the Milwaukee Brewers in 1982 while he was playing for Meramec Community College. He batted .399 for Meramec that year and only struck out once in 167 plate appearances. That year, he was named to the All-District team and the All-Midwest team. He also played for Meramec in 1983.

Repp continued his college ball at Southwest Missouri State, where he was named Rookie of the Year in 1981 after hitting a robust .432.

He played high school ball at Vianney High School from 1977-80, posting a .391 batting average that final season to earn All-Metro, All-District and All-Conference honors. That same year, he helped Crestwood advance to the American Legion World Series in Ely, Minnesota. He was captain and the leading hitter of his Crestwood team.

In 1981-82, Repp played for the West County Royals in the St. Louis Metro Collegiate League. In 1982, he led the Royals with a .362 batting average.

From 1983-87, he played for the Sotolar Pointers in the CYC Senior Major League. In 1986, Terry led Pointers with a .423 batting average, 80 hits, 17 doubles and eight game-winning RBIs. He was the MVP on the Pointers team in 1985 and 1986 and named to the all-star team three straight seasons. Repp spent five seasons with the Pointers and is ranked in the Top 10 in batting average, hits, doubles, triples and RBIs.