Simple, cheap, and efficient. If you want to simulate the pump from sidechain compression effortlessly and with negligible CPU hit, this is your solution. 16 waveforms with the ability to adjust when in relation to the beat the waveform is triggered and a choice of whether to trigger as a one-shot or sync to your host at eighth. quarter, half or whole notes. Made by the guys at Cableguys. And yes, there's a demo. VST/AU 32/64-bit. Works in every DAW I have.
$15, uses almost no CPU, and gets the job done. It's a no-brainer. If you want or need the sidechain effect and don't want to part with a lot of cash, this is your solution.