In Pokémon Ruby and Sapphire, Lavaridge Town is where you can win the fourth Badge. The town is in a volcanic region and is famous for saunas that contain spring water. A woman near the spring will give you an Egg that hatches about two hours later into a Wynaut.
Spring
Enter the hot spring through the northwestern door inside the Pokémon Center. Use your Itemfinder as you walk in the water. You'll find an Ice Heal.
Herb Shop
This shop is to the east of the Gym. Here's what is offered:
Don't buy too many of them, because if you keep feeding your Pokémon bitter items, its love for you will wane (unless you're getting TM21 Frustration). Talk to everyone in the shop. You will get a Charcoal, a hold item, that raises the power of Fire-type moves.
