Quick answer
A number is not a comparable price until its basis is known
Attach every amount to the exact item, option, unit or quantity tier, currency and date. Keep packaging, domestic delivery, service fees and international shipping on separate lines.
If the page does not state a field, mark it unknown instead of borrowing a value from another item.
Field note
Confirm what the amount describes
- Exact product or visible item code.
- Color, size, material or other priced option.
- Single unit, pair, set, sample or quantity tier.
- Currency and whether tax is stated.
- Date captured and source URL.
Field note
Keep cost components separate
| Component | Record | Do not assume |
|---|---|---|
| Item | Quoted amount and quantity basis | That every option costs the same |
| Packaging | Included, optional or unknown | That retail packaging is included |
| Domestic movement | Amount, included or unknown | That a source price includes delivery |
| Service or payment | Current stated fee | That a third party is free |
| International shipping | Separate estimate with package basis | That it belongs in the item price |
Field note
Normalize every candidate into the same record
Price comparison
Item and option: same comparison unit for every row
Quantity basis: one unit, sample, set or tier
Currency: as quoted; record conversion separately
Known included costs: list each one
Unknown or excluded costs: leave explicit
Source and date: URL plus capture date
Field note
Investigate a very low number before ranking it
A low amount may refer to a deposit, accessory, minimum tier, sample condition, incomplete option, domestic-only price or outdated page. Find the label attached to the number before treating it as an offer for the item you are comparing.
Field note
Use calculations only after the fields align
For a transparent comparison, add only known components that refer to the same item and quantity. Show currency conversion rate and date separately. Leave a landed total blank when packed weight, route or duties are not available.
Comparable subtotal = item amount + stated packaging + stated domestic movement + stated service cost. This is still not a final landed cost unless all remaining components are known.
Field note
Pause when the quote cannot be normalized
- No item or option can be tied to the amount.
- The quantity basis changes between candidates.
- The currency is unclear.
- Important inclusions are implied but not stated.
- The source or capture date cannot be recorded.
