Next time ask the woman if she wants to take it a step further and take The D-man's dinner while she's at it.

I had a woman call up wanting a product, and wanted us to match the online price. My coworker said "Well, we've never done that, but I'll go ahead and ask my manager for you." So she wrote a note for our boss and the next day I asked my boss (already knowing the answer) what the decision was. She went "So she wants US to sell it to her for the price an online warehouse sells it for?" Me: "Yup." Boss: "Ha!"

I left the lady a voicemail:
"Well, I went ahead and talked to my boss about the price. If you want it for $99 you're more than welcome to go ahead and buy it online. However, if you'd like to buy it from us that helps us, a local business, stay in business and support your local economy, then we'll be happy to sell it to you at our price."

A few days later she came in (driving a new legacy wagon) and was still trying to push for a discount.

Her: "I can get it for $30 less online and not have to pay taxes."
Me: "They sell it below our cost (not entirely true, or we would be ordering it from them too) so we just simply can't match that price without LOSING money on the sale. However, I can offer you actual customer service, let you handle the product before you buy it, and answer any questions you may have, face to face."

Sold it for full price

People that aren't involved in business, or that lack common sense, never understand that there's more to the bottom line than just a store's cost vs. a store's retail price.