# Billing and pricing: operator guides | PortaPro > Source: https://www.portaprosoftware.com/blog/topic/billing-and-pricing > > Rental billing for portable sanitation: 28-day cycles, prorated first invoices, cash discount programs, PO numbers and auditing what was billed. # The PortaPro blog Billing and pricing Rental cycles, proration, card fees, purchase orders and the invoices that never went out. [All topics](https://www.portaprosoftware.com/blog#topics) 5 posts [28-day billing vs monthly billing for portable toilet rentals](https://www.portaprosoftware.com/blog/28-day-billing-vs-monthly-billing) November 4, 2026 · 3 min read Thirteen cycles a year or twelve. Why most portable sanitation companies bill every 28 days, when calendar months make more sense, and the mistake that happens when a rate card is on one and the company is on the other. [Read the postarrow\_forward](https://www.portaprosoftware.com/blog/28-day-billing-vs-monthly-billing) [The prorated first invoice: what to charge when a unit lands mid-cycle](https://www.portaprosoftware.com/blog/prorated-first-invoice-portable-toilet-rental) November 4, 2026 · 3 min read A unit placed on day nine of a 28-day cycle should not be billed for 28 days, and should not be free until the next cycle. The arithmetic, the inclusive-day rule, and the line the customer should see. [Read the postarrow\_forward](https://www.portaprosoftware.com/blog/prorated-first-invoice-portable-toilet-rental) [Cash discount programs for portable sanitation companies: passing on card costs the right way](https://www.portaprosoftware.com/blog/cash-discount-program-dual-pricing-for-operators) November 4, 2026 · 3 min read A surcharge adds a fee to card payments and runs into card-network caps and state bans. A cash discount program lists the card price and offers less for cash, check and ACH. How the two differ, and how to set one up. [Read the postarrow\_forward](https://www.portaprosoftware.com/blog/cash-discount-program-dual-pricing-for-operators) [Getting paid by municipalities: PO numbers, per-site invoices and the proper invoice](https://www.portaprosoftware.com/blog/getting-paid-faster-municipal-customers-po-numbers) November 4, 2026 · 3 min read A city's accounts payable department does not pay invoices. It pays proper invoices that match a purchase order, one budget line at a time. What that means for how you bill parks, schools and public works. [Read the postarrow\_forward](https://www.portaprosoftware.com/blog/getting-paid-faster-municipal-customers-po-numbers) [The invoices you never sent: how to audit rate card billing every cycle](https://www.portaprosoftware.com/blog/why-invoices-get-missed-billing-audit) November 4, 2026 · 3 min read A unit sitting on a site with no invoice against it is the quietest way to lose money in this business. The five ways it happens, and the one report that catches all of them. [Read the postarrow\_forward](https://www.portaprosoftware.com/blog/why-invoices-get-missed-billing-audit) ## Other topics * [Routing and dispatch](https://www.portaprosoftware.com/blog/topic/routing-and-dispatch) · Planning the day, running it, and finding out what did not get done. * [Running the business](https://www.portaprosoftware.com/blog/topic/running-the-business) · Pricing, margins, growth, customers and the systems that hold it together. * [Drivers and the field](https://www.portaprosoftware.com/blog/topic/drivers-and-the-field) · Hiring, shared truck iPads, pre-trip inspections and proof that the stop was done. * [Septic and grease](https://www.portaprosoftware.com/blog/topic/septic-and-grease) · Pump-out intervals, reminder programs, licensing by state and grease trap schedules. * [Roll-off dumpsters](https://www.portaprosoftware.com/blog/topic/roll-off-dumpsters) · Tonnage, scale tickets, disposal pricing, swaps and overage days. * [Event and tent rentals](https://www.portaprosoftware.com/blog/topic/event-rentals) · Kits, pull sheets, counted items, site plans and layouts before the truck rolls. * [Choosing software](https://www.portaprosoftware.com/blog/topic/choosing-software) · How to compare the tools built for this industry, and what to ask on a demo. ## See it on your own book. Book a walkthrough with your own sites, units and billing cycle, or start a free trial and import your customer list tonight. [Start free trial](https://trial.portaprosoftware.com/sign-up) 14-day free trial (card required, no charge today). Or a guided 30 to 60 day trial with no card.