Each country-service price is tiered by its own cost — so WhatsApp-Nigeria ($0.20) is Low while WhatsApp-USA ($2.50) is High, independently. Set a markup per tier as cost × mult (the flat +cents is optional, leave at 0 for a clean multiplier). The Low tier carries the fattest margin and subsidises Mid/High to keep premium numbers affordable. Sample by cost below.

Numbers come from a pool of offers at many prices. The cheap prices hold almost all the real supply; the few expensive ones are a near-empty tail. Standard is the liquidity-weighted average of the pool after trimming that phantom tail — it lands on the real, buyable sweet-spot price (buy low). Priority steps a set % above Standard into genuinely fresher numbers. The chosen price is the real cost we then mark up with the tiers above.

Rentals hold the same number for days with unlimited codes. Each duration gets its own markup tier — aggressive on short impulse windows, gentler on the big long-term tickets — plus a retail floor (brand minimum) that rises with duration. A ladder guard in the engine keeps every ladder ascending: a longer rental can never sell at or below a shorter one, whatever you set here. Quote and charge run through one shared engine, so the sticker always equals the debit. The floor only ever raises prices — never what we pay upstream — so a loss is impossible.

Applied to the amount a customer pays when adding funds. Crypto only (BTCPay / NOWPayments): baked into the invoice rate — the customer is credited the round amount they chose, the markup is the spread you keep. PayPal credits 1:1 (no markup possible on a fiat rail).

One code per day. Post the ROT13 version to socials; customers decode it and enter the plaintext on the funds page. The first N redeemers get bonus credit; the rest see “today’s cipher is cracked.” Slot is consumed at Apply-click — the race is real.