Depends. Planet Jr. stuff included garden cultivators, edgers, generally manual larger garden tools. It was made by S.L. Allen Co. of Philadelphia, PA who also made Flexible Flyer sleds. The plain 6 3/8" number 2 and 3 solid Planet Jr. wrenches, sell for a dollar around here (within driving distance of Philadelphia. Cutout Planet Jr. wrenches generally sell for more. How much more depends on whether they are smaller (a lot more), equal to ($5), or larger than 6 3/8" ($15+).
Hope this helps. A caveat: I live on the East Coast where Planet Jr. wrenches are fairly common.