Well it's in Zeni, which is about equivalent to rela world Yen, which is about .01 dollars at this time, so it's really only six figures in American terms.
I mean, Goku was always a bit slow because he sustained a blow to the head when he was a baby. I know GT was written before Super happened but they made Goku really dim in Super so... I mean, it could fit canonically... if Akira Toriyama didn't pass away I feel like he would've redid GT, but with him actually in charge instead of being a consultant who designed SSJ4.