I have a cube of just Kamigawa block. As Stormcow said it works good thematically and mechanically. But more importantly for me, it feels complete. Like I have a complete boxed game of Magic now. I wouldn't even want to add the P9 because they wouldn't fit with the theme or power level.
Yeah, for the Peasant Cube that's probably roughly true. But take a closer look at the prices: first of all, LOTS of cards that are listed there as 15-25 cents you should be able to get for under 5 cents each. But second of all, notice the prices of Berserk, Force of Will, Maze of Ith, and Wasteland: that's over $200 for those four cards. Proxy those four cards and I bet you'll cut the cost of the Cube in half; proxy Baleful Strix and around 4 over >$15 cards, and you'll save another 60.
My estimate for the Peasant Cube is $200 if you proxy those cards.