Taxes and Duties
All imported goods for consumption, which includes toys and collectibles, are subject to payment of import duty which is 10% of the total value of the items plus the shipping value. You are also required to pay its value added tax (VAT) of 12%. On top of that there are also charges for the documentary stamps for the Bureau of Customs and Bureau of Internal Revenue which amounts to Php515. Taking all these into account, the total taxes and duties is almost the same as the value of the item. Thus, you end up almost paying double for the item. This is why sellers buy in bulk. The shipping cost is lower than buying single items and distributes the cost of the documentary stamps to multiple items.
Mall Prices
Gunpla kits significantly costs more in malls and department stores such as Toy Kingdom and Toys R' Us. This is because of overhead costs that is added on top of the item value after duties and taxes. Malls spend money on local business tax, employees, electricity, and other costs required to run a business. These costs are carried over to the merchandise while taking into consideration that a kit will not sell quickly. And of course, they need to make a profit.
Independent and Online Sellers
Generally, you can get cheaper deals with independent sellers and online sellers. Independent establishments usually have fewer employees (or the owner runs the shop himself), a smaller real estate, and more concentrated on a specific market. This lowers their overhead costs, which lowers their prices.
Online sellers eliminate much of the overhead costs because they usually sell and deliver their merchandise themselves. They do not need to rent a space for their establishment or pay utility bills since they usually work and stock the merchandise in their own houses. They may have a limited quantities but they sell their items at a much cheaper price.