Use these sort of like Doors - They have IDs, so Doors can lead to them, though you can’t travel from them. Use your wrench to set their ID.
Path Marker price in Growtopia: sells for about 20/WL (median of 721 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: TYBUYS, TEKOI, GATESHELL, 37OI, SUNJO