Glowcaps are scattered around the western part of the Zangarmarsh area. If you’re a Herbalist, you can see them as yellow dots in your mini-map. You can turn in 10 Glowcaps to level your rep with the Sporeggar faction until you become friendly with them. After that, you can use your excess Glowcaps to make gold.
Glowcaps can be used to buy faction rewards from the Sporeggar. There are two cooking recipes from the Sporeggar quartermaster that look promising.
Recipe: Clam Bar
Only Mycah sells this cooking recipe. It costs 1 Glowcap but you can resell it on the Auction house for at least 5 Gold, depending on the prices on your server’s Auction House.
Recipe: Sporeling Snack
Sporeling Snacks are favorites of hunters and warlocks. Plus it is an excellent recipe to level your cooking skill with. You pick it up at 310 and it grays out at 350 cooking. The recipe costs only 2 Glowcaps but it can be sold on the Auction House for at least 10 gold.
As you can see, Glowcaps can help in your quest for WoW gold. You can also sell Strange Spores that are needed to make the Sporeling Snacks. Strange Spores are dropped from various monsters around Zangarmarsh.