About this block

Buy Once Math Card runs two mono ledgers side by side: one Field Pack over ten years with two published bench repairs comes to $21.50 a year, the $60 bag replaced every 20 months comes to $36.00. The left column balances the ledgers with three printed caveats, the sharpest being "A bag abandoned in year 2 is the most expensive line on this page." The resale program appears as the escape hatch if the math fails in practice, not as a pitch.

Two arrays drive the block: one for ledgers with nested row arrays, one for caveats. Mono font on the card side makes the arithmetic the visual.

When to use

Reach for this block after the pre purchase checklist on a buying guide, or in the FAQ as the cost per year answer. The bench repair rates cited must match the live published rates or the arithmetic becomes dishonest.

A natural flow around it on an Ecommerce Pro page:

Before

• Pre purchase checklist

After

• Second bag advice
• Resale sections

What you can display

One strong use is the ten year two ledger comparison. Other decade math editions:

• Subscription vs one time. The cost per delivery versus the upfront bundle over two years.
• Repair vs replace. The single unit math when the bench quote arrives, before the decision.
• Trade in timing. The year by year resale value against a straight hold, the break even named.

Tip: printing the caveats beside the math is what separates it from a sales calculator; the "only works if you actually keep it" line is the integrity of the block.