Price first: You're only getting 40 yards of yarn for $25 or 55.5 yards for $38. That strikes me as a mite high; I think you're paying something for the handspun factor. A larger problem is that the seller only has one skein of each color available. You're very limited as to what you can do with 40 yards of yarn, even in a very bulky weight. The seller says she "doesn't have the attention span" to spin many skeins of the same yarn. Fine, but not very practical for a customer who actually wants to use it for a sweater, vest or bag.
As to what you could
make with it, here's a cowl knitted with one skein of Colinette Point 5, a somewhat similar thick-and-thin commercial yarn.
(One skein of Point 5 is 50 meters, or about 55 yards. I think it's been discontinued, but there are still some quantities available online for prices ranging from $19.00 to $25.00.)
You could probably get a beanie out of one skein of the Guttersnipe yarn. Or wrist warmers. If you love the look and don't mind the price, you could have something small but unique.
If you want to graduate from Walmart yarn and get some idea of what good (but not necessarily spectacular) yarn costs, look at knitpicks.com. for basics, or try elann.com, which has deep discounts on great yarn.