Starcraft RPG - HOw can i download starcraft for free?

HOw can i download starcraft for free?

By "stealing" it. That's usually how you get something that costs money for free. i don't recommend you do. If you use a file-sharing program to get it, you can be prosecuted or fined if you are tracked. It's not worth it, especially since you can probably find it on eBay for less than $5.
Email the publishers of starcraft and tell them you want to pirate a copy of their software that other people pay for. I am sure they will assist you in some way.