What software I need to buy to work with Cyclon III dev. board?

Hi Ighiz,

for a Cyclone III FPGA, you can use the free Quartus web edition. You'll also need a simulator and here too you can use the free ModelSim-AE web edition.

Just to make sure we're on the same page, an IP core is more or less the equivalent of a software library.

The 995 USD price for the Embedded IP suite is a one time cost. You buy the it and then you can use it forever in your designs.

The Quartus II subscription does include some of those IP cores.

But you can test the IP cores included in the Embedded IP suite for free, so I suggest you don't go an buy it straight away. Unless you have a schedule for spending.

If you have the time to research it, you may want to consider other IP sources than Altera.

For example, at OpenCores.org, you can also find a decent 32-bit CPU and 10/100 Ethernet controller.

There's no free DDR2 controller AFAIK, but there are other comercial ones (Beyond Semi, for example).