The customer bought 10,000 units. What happens next?
July 15, 2026
A customer buys 10,000 usage units for SAR 2,000. Their plan also includes 1,000 units every month.
During July, the team uses 3,200 units. They finish the month with 7,800 available.
That simple balance hides the decisions that make prepaid usage feel trustworthy: what a unit buys, which units are spent first, when top-up runs, and whether unused units expire.
Prepaid usage puts a ceiling on spend
Usage-based billing usually charges after consumption. The customer sees the final amount at month-end.
Prepaid usage reverses that order. The customer chooses an amount first, then consumption draws it down. Their maximum exposure is visible before the work starts, while you collect before carrying the usage cost.
This model works well when:
- every operation has a real variable cost;
- monthly usage changes significantly;
- the customer wants a fixed budget;
- or uninterrupted work matters more than approving every usage charge.
It does not replace the meter. The meter still records what happened. Prepayment only changes when the customer pays.
A unit needs a visible value
“One unit” means nothing until the customer can connect it to the product.
For the report product:
| Product action | Units used |
|---|---|
| Standard report | 4 units |
| Report with web research | 10 units |
| Large data analysis | 25 units |
The customer should see this conversion before starting the action. If the price appears only after consumption, units become a second currency they cannot predict.
Keep the conversion stable enough to plan around. When the underlying AI cost changes, update future pricing deliberately instead of silently changing what existing units buy.
Keep the source of every unit
The customer has two types of units in July:
- 10,000 purchased units from the SAR 2,000 pack;
- 1,000 included units that arrived with the monthly plan.
After 3,200 units of usage, 7,800 remain.
11,000 units in, 3,200 used, 7,800 available
Plan units are used first because they renew monthly. Purchased units remain according to the agreed expiry policy.
The total is useful, but the source matters. Included units may renew monthly while purchased units last longer. Promotional units may expire after a campaign. A service credit may follow different refund terms.
One number on screen can represent several buckets underneath. Keep each bucket’s origin, date, and expiry so support can explain the total.
Spend the units that expire first
In this example, the 1,000 plan units renew at the end of July. The purchased units remain for twelve months.
The sensible order is:
- use the 1,000 monthly units;
- then draw 2,200 from the purchased pack;
- leave 7,800 purchased units available.
Spending the long-lived purchased units first would leave the customer with monthly units that disappear days later. The displayed total might be correct while the policy works against them.
State the order before purchase: earliest expiry first is easy to understand and usually protects the customer’s value.
Top-up should prevent an interruption
The customer can buy another pack manually, or set an automatic rule:
When available units fall below 1,000, purchase another 10,000 for SAR 2,000.
The rule needs a threshold, pack size, payment method, and spending cap. A cap protects the customer if usage suddenly spikes or a faulty integration creates unexpected operations.
Send a notice after each top-up with the amount paid and new unit total. The customer should never discover an automatic purchase only from the card statement.
Expiry belongs beside the purchase
If purchased units expire after twelve months, show the date before payment and keep it visible afterward. The same applies to whether units can be refunded, transferred between workspaces, or carried into a new contract.
Avoid one expiry rule for every source. Monthly included units, paid packs, promotions, and service compensation serve different purposes and may need different terms.
In Tirdad, each customer can have a unit wallet with separate entries for purchases, plan grants, promotions, and usage. The ledger keeps every addition and deduction, top-up rules run at the threshold you choose, and the product can show the available amount from the same source.
Prepaid usage works when the customer knows what each unit buys, where the available amount came from, and when it changes.
Eight connected decisions—from the first usage event to recurring revenue.
Set the rule once. Tirdad applies it every time.
Keep the policy, effective date, customer agreement, and invoice calculation in one billing system instead of rebuilding the decision in every product surface.