[neatoman]

That depends on wheter or not Jennika remains (becomes?) popular. Remember a ton of new characters were created in the 90's to bait speculators. And indeed, New Mutants #98 does fetch a hefty price, but what about Youngblood #1? About 20 Dollars or so in an honest auction, 150 if you "buy now" but I doubt anyone will go for that. Spawn #1, a series arguably more relevant than Youngblood, sells for about 40 dollars and maybe 100 if it's in fine condition.

Judging from the response I see here and elsewhere... I honestly don't know if Jennika's time as a turtle is popular enough to warrant a high price in the future. People mostly seem annoyed she's part of (if not synonymous with) a questionable story arc about a slum, and personally I question if she'll even remain a turtle in the long run. It almost seems like she was mutated for the sole reason of temporarily ratcheting up the sales artificially, you know like... Having Peter Parker's clone come back, replacing Superman with an evil cyborg or breaking Batman's back. The whole thing just stinks of being a gimmick to renew interest.

So yeah, even as a character in the IDW series I doubt she'll stick around forever.