# Billing

> Prepaid balance, what you are charged for, and currency.

Source: https://developers.qartvelo.com/advertisers/billing

- **Prepaid.** Campaigns spend from your account balance. Qartvelo Ads tops up the balance after you pay; contact Qartvelo Ads for an invoice or bank transfer details. Every top-up and adjustment appears in **Billing** with its date and note.
- **Currency.** All prices, budgets and balances are in Georgian lari (GEL).
- **Charged per impression.** One impression costs your CPM bid / 1000, charged when the ad was actually displayed and the impression passed validation. Clicks are free.
- **No overspend.** A campaign never spends more than its total budget, its daily budget or your balance; budgets are reserved per impression atomically.
- **Invalid traffic is free.** Duplicates, replays, expired ads and events rejected by fraud rules are never charged. Test traffic is never charged.
- **Balance runs out.** When your balance cannot pay for another impression, your campaigns stop serving until it is topped up. Top-ups reach the ad server within about a minute.