Which is the best and affordable business process simulation software?

Try Simul8. You can export the process in BPMN 2.0 from your IBM Blueworks live and import them into Simul8. 

I agree with @Ian Ramsay ​that most process mining tools and monte-carlo sims won't get you what you need. 

We have had excellent results in projecting costs, savings, identifying waste (time and materials) issues in a service centre/case management scenario, a hardcore food manufacturing environment that involved a high volume automated production line with human interactions, a financial lending evaluation/approval scenario, and an arts grants case management scenario. 

See Business Process Analysis and Costing (BPAC = Activity-Based Planning + LEAN) noted in my earlier message below.

Rich and realistic simulations are both fun to watch and can be most informative.  Unfortunately, they are difficult to overlay on a vanilla-flavoured BPMN diagram model.  Simulations need much more context and data than produced by Blueworks or BPMN, to be realistic or rich.

Process simulations are typically
- replays of actual case logs as seen in some process mining tools (Fluxicon)

- monte-cargo generation & analysis of synthetic case logs for process improvement (AnyLogic), or

- interactive walk-thru sessions for staff training and acceptance (Trisotech)

In my opinion, the unfounded approximations one has to make regarding unit costing and the statistical distributions of other metrics render most such simulations unrealistic. 

But fun to watch...

Process simulation has been around for a long time and there are lots of tools that can take BPMN models and iterate through the steps... but frankly, there is not much-added value for your client in doing that. The reason I say this is that the time and cost results coming out of your process model likely will not take into consideration different labour rates for people doing different roles or activities in the model, will not include some percentage of supervisor or management time, will not consider (or allow you to play "what-if" with the mix of employee versus contract help, will not consider the other overhead things that affect process costs like fixed and variable resource costs (i.e. machinery, a physical office or industrial space, etc..). And how would you look at capacity and utilization numbers/percentages, unit and total service costs, etc? 

These are the things that would be of value to your clients, along with the ability to build out and analyze value stream models in conjunction with your simulation to help LEAN those processes and compare possible competing scenarios... 

Think Digital Twin but at a process level that is easy to build, provides complete analytical capabilities and adds a REAL value. Here is a link to a presentation on Business Process Analysis and Costing (BPAC = Activity-Based Planning + LEAN) that integrates process/operational optimization, service/product cost optimization, and resources optimization. You should find it interesting. This is a cloud-based cost-effective solution based upon the QualiWare EA toolset. 

After the video, if you want to find out more please contact me directly. Implementing LEAN Business Process Analysis & Costing (BPAC) via CBP - YouTube

ARIS

Automation Anywhere