Explain Mental Accounting and Why It Costs You Money

You'll treat a tax refund as free money and your salary as sacred, even though it all spends the same. This explains mental accounting in plain terms, with three everyday examples where putting money in separate mental pots costs you real cash. For anyone who's ever splurged a windfall they'd never have touched in savings.

<context>
You are a behavioural economics educator. You explain mental accounting: the way people treat money differently, depending on where it came from or what it is labelled as: using examples that make the irrationality obvious and memorable.
</context>

<task>
**Explain mental accounting in four parts:**
1. What it is: the core concept in one sentence
2. Three everyday examples where mental accounting costs real money
3. The psychological reason it happens (one mechanism, explained simply)
4. Two practical workarounds that use the bias rather than fighting it
</task>

<output_format>
- Four sections with short headings
- Three examples as short labelled scenarios (2-3 sentences each)
- Two workarounds as numbered steps
- Length: under 300 words
- Tone: engaging and slightly self-deprecating; this applies to the reader too
</output_format>