George Brett was one of the biggest stars in Major League Baseball during the late 1970s and 1980s, making baseball cards from his career some of the most sought after from that era. As one of the best third basemen to ever play the game and a career .305 hitter, Brett’s cards from 1980 in particular hold significant value, especially his rookie and star cards.

Brett was already an established star by 1980, having made his MLB debut in 1973 with the Kansas City Royals at age 20. In his rookie season he hit .282 in 103 games to finish third in AL Rookie of the Year voting. Over the next several seasons, Brett emerged as one of the game’s premier third basemen, making the AL All-Star team in 1976 and 1977 while consistently batting over .300.

Entering the 1980 season at age 27, Brett was coming off back-to-back 100 RBI seasons and was a four-time All-Star. That year he would have one of the finest individual seasons in baseball history, batting an incredible .390 which remains the highest single-season batting average of the post-1960 expansion era. Brett’s 1980 campaign is considered one of the greatest offensive seasons ever, as he also led the league with 118 runs scored, 90 extra-base hits, and a .664 slugging percentage.

Brett’s dominant 1980 season made him one of the most sought after players for collectors. His rookie cards from 1973 held value, but his cards from 1980 skyrocketed in demand. Below is an overview of some of Brett’s key baseball cards from 1980 and their estimated average market values in various grades:

1973 Topps #138 Rookie Card: In PSA 10 gem mint condition, Brett’s coveted rookie card has sold for over $15,000 in recent years. In PSA 8 very fine-excellent condition it averages $500-1000, while a PSA 6 good condition example can sell for around $150-300.

1980 Topps #1: As the #1 card in the set, this is Brett’s main flagship rookie star card from his epic 1980 season. In PSA 10 condition it averages $1,000-2,000 at auction. A PSA 8 copy sells for $300-500 on average.

1980 Topps Traded #124T: This traded set variation features Brett in a Royals batting stance. PSA 10 copies have sold for $800-1500. PSA 8 grades bring approximately $200-400.

1980 Fleer #132: Fleer was the other major brand alongside Topps that year. PSA 10 examples of Brett’s card average $600-1000, with PSA 8s at $150-250.

1980 Donruss #34: Considered one of the more scarce 1980 sets, Brett’s Donruss card still holds value. PSA 10s have sold for $500-800, with PSA 8s around $125-200.

1980 Post Cereal #46: This is one of Brett’s more iconic cards from the year featuring a cartoon-style illustration. PSA 10s go for $400-700 on average, with PSA 8s at $100-175.

1980 TCMA #3: This is Brett’s card from the lesser-known TCMA (Trading Card Merchandisers Association) set that year. Even PSA 9 copies can sell for $150-300 given the set’s scarcity.

In addition to his base cards, Brett also had several notable inserts, parallels and variations that hold premium value:

1980 Topps Mini #1: This miniature version of Brett’s flagship card has sold for over $1000 in PSA 10 condition.

1980 Topps Stickers #S1: Brett’s sticker card in top-grade can bring $500-800 at auction.

1980 Topps Traded Tiffany #T124T: The ultra-rare Tiffany parallel of Brett’s Topps Traded card has sold for over $10,000 in PSA 10 condition.

1980 Fleer Stamp #132: Brett’s “stamp” parallel from Fleer is also extremely scarce. PSA 10s have sold for $3000-5000.

In summary, George Brett’s baseball cards from his epic 1980 season are among the most coveted and valuable from that entire decade. As one of the true icons of the 1970s-80s Kansas City Royals, Brett’s rookie cards as well as his flagship cards commemorating his 1980 MVP campaign will always be in high demand with collectors. In top grades, examples can sell for thousands due to their historical and nostalgic significance.