There are plenty of options with free electricity. You might want to make a small research here.

BUT If your electricity is free for a limited time, you might still want to consider your costs for the future - by choosing the right mining algorythm, a stable rig, etc. Otherwise, whatever you mine for free you might loose when you have to pay the costs.

If you have never been mining, it is easier to buy a plug-n-mine rig, not build your own.

Also, what amount are you planning to invest, that will also help while choosing the rig options.

The other thing, there still is someone who is paying your electricity bills...