DCS are offering those considering different modules a free 14 day full trial. Each module can be downloaded either at once, or consecutively, meaning you get to try before you buy.

The 14 day trial can only be taken up once every six months.

See here for details

All newcomers to DCS get a 50% discount on their first purchase.

You can buy anything from one module to the entire library with 50% discount

See here for details.