MIMIC Simulator supports up to 100,000 simulated devices on one computer. The software is licensed by the number of simultaneous agents you want to access.
Your main purchasing decision is how many agents you want to run simultaneously. You can buy a license starting at 1 agent up to 100,000 agents. There are many price points in between - 5, 25, 50, 100, 250, 500, 1000, 2000, 3000, 5000, 10000, 20000, 50000 and 100000. The price per agent reduces dramatically as you go for the higher scalability. For example, the cost of 500 agent is not double that for 250 agents, but only a fraction higher.
Some vendors offer "unlimited SNMP agent simulation" license keys. The problem with such a scheme is that it hides the ultimate cost of scaling to a large number of agents. In practice there is a limit to the scalability of SNMP agent simulation, imposed by a combination of the hardware, the operating system, and the vendor software implementation.
By making this license cheap upfront, once the first purchase has been made, the vendor locks the customer into having to buy multiple licenses to scale up to the desired number of agents. Furthermore, due to the economics of the arrangement, the vendor has no motivation to increase the scalability of their solution.
Moral of the story: get the true cost of scaling up to many agents up front, to avoid higher costs in the long run. By evaluating a solution with a large number of agents you can calculate the true cost instead of facing the surprise later.
MIMIC Simulator offers "true cost" licensing. You pay for a number of agents upfront, and by evaluating that number of agents you feel confident that the solution will handle the desired number of agents at a predictable cost. Furthermore, by offering a cost-effective upgrade path, you can purchase a smaller license first, then when the need changes, you can easily upgrade the license,