DE0-Nano-SoC develop environment, free version of IDE?

Quartus Lite comes with everything needed to work with the SoC ARM processor. You will need to separately download the embedded development package separately (at no charge). This will give you what you need to develop Linux applications and kernel drivers. This is the ARM DS-5 eclipse based environment. The free version does NOT include the ability to develop stand alone software for the ARM. My understanding is that others have found ways around this, but I've not this, so I haven't investigated.

Having said all this, I don't recommend an SoC based board for a beginning hardware engineer who wants to develop Verilog/VHDL. Instead get a Non SoC based board in the same price range. You will find it has a larger FPGA and probably more stuff on the development board.