Is there an App to run Windows on my iMac without having to buy Windows?

I have a camera that needs a "firmware update". The software to do this came with the camera on a CD. Unfortunately it's PC software (.exe)

I contacted the manufacturer of my camera for a Mac version but thay don't have one.

I'm aware of Boot Camp, but I wonder if there is a relatively cheap app available that would enable my iMac to boot a Windows app just long enough for me to update my camera. I want to avoid having to fork out for Windows if possible, what with it being rather expensive for what will, most likely, be a one-off job. I also wouldn't know what version of Windows I would need either.

Can anyone recommend an emulator or something that I may install?