I was picking up some oil, and saw a sign that read: Oil X or Oil Y and Filter Z $Price A. I glanced over the ad and emphasized the OR, assuming (surprisingly) that I could get the good price without buying the filter. Not logical, but that's how I read it!
My purchase rang up full price. I asked about the promotion. We walked over to check out the sign. She said I needed to buy the filter. I was convinced that I didn't. I was also ready to fight for my savings.
The salesperson did not have a commanding grasp of the English language. As a result, I got her so confused that she sounded like she was agreeing with me, reading the sign with the emphases I was placing on OR. However, she insisted that I did not qualify for the promotion. I kindly asked for a supervisor.
The supervisor, clearly a native English speaker, read the sign as intended. He emphasized the AND part of the advertisement. Immediately, it clicked in my brain and I was ashamed to have made a scene at the auto parts store. However, I would make the following revision to the sign in order to increase clarity: Filter Z and either Oil X or Oil Y for $Price A. By placing the AND in a preeminent position, it removes most of the ambiguity in the signage.
The original saleswoman was a saint who tried to return the oil filter I had purchased online and replace it with the one featured in the promotion. However, they did not have it in stock.
So I loudly apologized for acting like a child and loudly thanked them for all their help. They were clearly right and I was clearly confused.
I blame grammar. That's my story. Im sticking to it.