Way to do Buy one get one half price sale on basic Commerce plan?

I would love to do a buy one print, get one half price sale on a particular print product in my shop. I only have the basic commerce plan and can't afford to upgrade at the moment. Is there a way around this anyone clever can help me think up? I really need to create a promotion in the run up to Christmas as things are really tight here.

if it's buy 1 get one half off on 2nd of the same print, you could do a variant -- variant one would be price of 1 print (e.g., $50), and second variant would be for 2 prints with the discount reflected - e.g., $75. 

if the promotion applies to any print you are selling (provided the price is the same for all your prints), you can create a new product, add the 2 variants, and then put a form in for your customers to specify which prints they want.

Thanks sruss76. I did wonder if something like that might be the only way. Sadly all the prints are different prices, sizes, media, so I might just put the special offer on one of them for starters so it doesn't get too complicated. Much appreciate your help, thank you.