You can either buy the system in world or on the Marketplace. To buy on the Marketplace touch the window above to open the DCS page on the Marketplace. We would like you to keep in mind the US dollar price on the Marketplace does not reflect current Linden Market value. It reflects what they charge you if you use your credit card or paypal. It is more cost efficient to buy the Lindens first on their main page than use the real life dollar amount of the Marketplace.
To buy in world select the link below according to the Region you are in. If you have never used an slurl link before, selecting the link will pop open another web page showing a map, you select teleport now and it will open a landmark in your Second Life Viewer. Select the option to "Show on Map" and it will open your map and show you the location of the DCS vendor, proceed accordingly.
The DCS is 75 linden and comes free with melee weapons. You receive free updates and your DCS will work in any SIM. When you teleport to various sims your DCS downloads the "game" for that SIM so there is no need to buy another ever. If there isn't a configuration set up for that sim your DCS will default to a global configuration.