The first conclusion is of practical and of legal nature: It does not make sense to order hardware in a foreign country, or to buy large amounts of hardware when you travel. One the one hand, shipping cost will eat up all cost advantages. On the other hand, you'll have to pay custom duties or an import turnover tax for many products. The only exception is the purchase of inexpensive products, as consumers in different countries can often buy goods abroad that remain below a certain price level without having to pay duty charges.
Meanwhile, the price differences between different PC products are remarkable. Basic consumer electronics accessories such as a 2 GB SD memory card vary in price around the world by up to 100%, while prices for premium PC components vary by 10-30%. Cost for a Core 2 Duo E6850 processor or a GeForce 8800 GTS graphics card was very much balanced, while the Coolermaster power supply or the Zalman CPU cooler showed large pricing differences. We selected products that are available almost everywhere, and we took the average price of the four cheapest etailers to get a solid number.
We found that France is rather expensive, especially if compared to Germany, which is next door. The United States is at the other end of the pricing spectrum, as most products are less expensive there.