Don't bother with the Troopa Shell as the Masher is still more powerful. Buy the Parasol for Peach, the Double Punch for Geno and the Ribbit Stick for Mallow and equip everything. The next two doors lead to one large room where you can find a weapons and an armor shop. Here you can buy a beetle cage to play the beetle game on Booster Hill if you want. In the left building, the first door leads to the Beetles Are Us store. They sell almost every item you got up to this point in the game, plus some new ones.
Now that all the townspeople of Seaside Town are back, the shops are open for business.
