You would ask Sprint or Verizon for such. I don't see such an offering today but you could expect to pay about 2 to 4 times the monthly rate of the normal service for this. The reason for such a number is about what you see for pay as you go type service.

The costs to field this service are fixed (signup costs, network etc.) So to get a monthly I'll just use it for this month and cancel will incur more fees than you would expect.