I just sold some concert tickets for my son. The first buyer bought all 3 and turned into a NPB.

Very frustrating when there is a time limit to sell something....so I next listed them as immediate payment by Paypal, they sold and were paid for within about 8 hours. 

Best to list as immediate payment.

I listed the 3 as BIN with the option of purchasing as many as they wanted...had one single purchase, then one for 2 tickets. 

Possibly list yours as 2X ...for a single purchase of the 2 for $240 rather than $120 each with 2 available as you may be left with one unsold.