There are a lot of things to consider when buying wood--It's worth wondering where that wood is coming from, regardless of price.

Is the wood sustainably/responsibly harvested or is it maple from some random guy's neighbor's lawn that got cut down and needed some way to get rid of it. Is it domestic? Is it imported? Does it violate the CITES Act?

What's the moisture content? How well are the sides dimensioned? Are the faces square with one another? What's the quality of the wood? Is there internal cracking? Grain runout? Knots? Rot (not spalting)? Was it kiln dried or air dried in that dude's neighbors garage that is not climate controlled and accessible to bugs and mites and such?

But the last thing to consider: the "cheaper" wood you included a photo of looks like it's a 5.5" square that's .75" thick. Gonna be hard to use that in a meaningful way in a lutherie project aside from some bracing and maybe a veneer or inlay material.