Final answer:
The commercial lease in question is a percentage lease, requiring a base rent plus a portion of sales.
Step-by-step explanation:
The lease described is most likely a percentage lease, which is commonly used in commercial real estate, particularly in retail. A percentage lease agreement stipulates that a tenant pays a fixed base rent, which in this case is $1,000 per month, and in addition, a percent of their monthly sales, here being 25% of the sales. This type of lease provides an opportunity for both the landlord and the tenant to benefit from the success of the business, allowing the landlord to participate in the tenant's profitability.