The short answer
At 500 units most US property management software costs $500 to $1,300 per month before one time fees. Per unit pricing is what drives that: Yardi Breeze, Rent Manager Basic and Propertyware Basic all land near $500, AppFolio Core is reported near $745, and Buildium's plan floor plus one online rent payment per unit puts it at $700 to $1,240.
Letting costs $224 per month at 500 units billed yearly ($2,688 a year), or $449 month to month, the same price it costs at 151. It does not collect rent, screen tenants or list vacancies. Tenants keep paying into your bank account and Letting reads the bank export, so no payment fee grows with your door count.