There are four different options to buy your Bux: two regular blue packages, a silver package, and a gold package. Each package gets more expensive as you buy more Bux, but the cost of an individual File:Bux.png goes down. The table below shows the cost of each packet in both USD and GBP, and the cost per File:Bux.png for each package, as shown in the two pictures from the in-game menu.