While this isn't an exact science (since expensive reprints will limit the price of new cards, which might be hurting the Bant deck a bit, since it has the highest-value reprints), this system works pretty well in general
$3.99 Peter Parker Marvel's Spider-Man $0.49 Spider-Man 2099 Marvel's Spider-Man $3.99 Gwen Stacy Marvel's Spider-Man $1.29 Arana, Heart of the Spider Marvel's Spider-Man $5.49 Miles Morales Marvel's Spider-Man $0.49 Scarlet Spider, Ben Reilly Marvel's Spider-Man $0.35 Aunt May Marvel's Spider-Man $0.49 Silk, Web Weaver Marvel's Spider-Man $2.49 Spider-Woman, Stunning Savior Marvel's Spider-Man $2.79 Spider-Punk Marvel's Spider-Man $0.69 Radioactive Spider Marvel's Spider-Man $3.49 Superior Spider-Man Marvel's Spider-Man 0 results found
Over the last few years, the card has gained a lot of traction
And you have your opponent to thank for it
In terms of value, the difference can be tens or hundreds or thousands of dollars
Anathemancer Anathemancers ETB hits a player only once, but you can unearth it later to do it again