How I wound up with a free avocado at Key Food

I went to Key Food for pop and provolone. Coke product pop sale was 4/$4 (must buy 4, with $10 purchase) and the 7up products were 4/$5 (must buy 4).

I got provolone ($5/lb) and a half pound of salami ($6/lb) and wound up with a bit over a pound of provolone. I also had an avocado in my basket. I got out my calculator, since math in my head is too hard, and found I had $9.81. So I got an overpriced lime for $0.25, picked my 4 pops, and went to check out.

The pops rang up at $1.89 each, not the sale price. I questioned it, and the cashier told me it was from the bottle deposit and tax. I questioned that, so she asked her manager. The manager added stuff up in her head and said I was short of the $10. I thought I had double checked, but I could be wrong, so I said I'd grab one more thing to put me over. They said I was about an avocado short. I like avocados enough, so I got another one, and the price came down, and I left.

Then I looked at my receipt and saw only 1 avocado on it!