On the third day of every month, every stores in Neopia sell it's stock at 1/2 price. This is the day where you go and buy things that are well too expensive on normal days and if you want resell it at your shop for a profit.

Some of the shops I will shop at is:
Faerieland Bookshop
Booktastic Books
Neopian Pharmacy

However, the Hidden Tower and Smuggler's Cove are the only two shops that don't cut their prices.