I doubt we're going to ever find a "budget-per-episode" figure here, guys, it's not Lost or something where there's enough of an audience to even bother documenting that in a public sense. Yeah, of course it was big budget for a Nickelodeon show, which basically says nothing at all. It'd be significantly less cash than, say, early-days Buffy, which was considered a cheap cable show even for '96. I guess Animorphs'd be similar to something like Alex Mack (which was obviously far more genuinely great than AniTV), or their other live-action stuff from the period. Likely less than the Goosebumps series, which was actually successful.
As for the "I hate it because it was a cash-in" argument, it's valid, but again what would you expect? Any crossover-medium thing with a book series, especially while it's popular and still in circulation, is a cash-in. Let's just be honest here with the reality of this not exactly being Game of Thrones or Walking Dead or whatever, it was a quickly-hashed-out afternoon series on Nickelodeon, aimed at elementary kids. There's nothing wrong with that, really. We don't seem to whine about stuff like Ninja Turtles, which started the exact same way, a sanitized version of a somewhat-popular-but-niche property to make the most of the license.
And, also, to be fair, we'd all hate any Animorphs series that was suitable for kids (not in K.A.'s sense, in a television executive's sense of the term) and financially viable. Of any description. That's not their fault.