Multisite Installation, setup, management

1) How may I add the option for multisite on my dashboard?

2) How can I add a theme with directory and classified plugin

3) Is WPMU TRIDEN, WMPU NELO, SIMPLE MARKET, Farms 133 Theme Pack available for use? If so, how much.

4) I viewed my next subscription bill and it’s $207. Did I install a plugin with a monthly cost to it?

Note: Today, I discovered that certain plugins require multisite activation.