As you may know Frozen Synapse is coming out tomorrow.
You can still preorder it. http://www.frozensynapse.com/synapsePreorder.html
If you enter the code STANCHER during the processing order you'll get an additional 30% off offer, which makes the single copy 13,29€ in Europe for example. I think this offer is worldwide.
Once you select PAYPAL, there's no more oppurtunity to enter the promo code. You can enter if you choose credit card though.
edit: Actually, choose credit card, click next, enter code, go back and choose paypal and it lists the discounted price when you go to login to paypal.