I can't do that but I will be happy to explain the difference between negotiation and haggling.

Haggling: one party publishes a high price, the other party presents a lowball offer, and they stubbornly give up a little ground at a time until they meet more or less in the middle. Typical alternative to a successful haggling is to walk away; this is often the threat held out by the parties.

Negotiation: the parties first agree upon a desired end state and work together to invent scenarios to get to that desired end state; the parties don't cling to positions but rather attempt to satisfy interests.

If you had "negotiated" rather than "haggled" you might have wound up with a better deal. Instead, by using the single variable of how much currency would be exchanged, you limited your options. Very simple example to illustrate that is this: it costs the shopkeeper about half retail to "give" you something like a pair of shorts or a helmet. The perceived value of that thing to you can be greater than that. Service may cost him nearly nothing on a marginal basis to "give" you, but has a perceived value to you.

In contrast, the perceived value of a dollar to each of you is identical.

You're not unique. And most shopkeepers don't know how to negotiate either.