If it is a business project where you have to show how you make a business move and try to sell something then surely part of this project would be to illustrate the purchase of a license for the software you made.
You will get extra marks for this, trust me.
If I was your teacher I would certainly give you marks for buying a license and subtract marks for running a business or being an enterpreneur who uses pirate software.
Your project is trying to be a real world example. You don't want real world problems by not paying for a license.
Actualy this license cost, as with any other costs, should reflect on the pricing of the product you are trying to sell.
Alternatively ask from your school to fund the license. Debate see where it gets you. Success or failure is not important what it is is the experience you will gain, your negotiating skills will improve and be tested and you might even win a license fee.
There... I gave you a bit of material to think and include and write to your project. As a matter of fact I would use the content of this thread as an appendix on mine!
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Pointy birds, Oh pointy pointy
Anoint my head, Anointy 'nointy