You can set up a 2 for 1 offer by creating a 50% Discount and setting a Basket Validation Rule on your Price Table that limits the applied Discount to 2 tickets in a basket.
This will mean that when the user applies the coupon code, it will make the basket amount 50% off the price of 2 Full Price tickets.
Create a Discount (See our Guide for full instructions) - promo offer: 50% Discount - this will take off 50% of the price of 2 tickets in the basket
Basket Validation Rule
Go to your Event's Price Table
Create a New Basket Validation
Set a Rule that the basket:
Must have at least 2 tickets from your chosen Discount
Can't have more than 2 tickets from your chosen Discount
Only if the basket has at least 1 ticket from your chosen Discount
This means that when the user adds 2 Full Price tickets in the basket and applies the coupon code, it will turn the 2x Full Price tickets to 2x 50% discounted tickets.
Applying Discount on the Box Office page
On the ticket page, click Add Discount either:
Before you select any tickets and select the discounted prices to add to your basket
Or after you select the full priced tickets and the Discount will take the price off the basket value
Depending on which discount option you go for, it will take either 50% off both tickets or 100% off one ticket