Postpromoter has their code open source : https://github.com/MattyIce/postpromoter. As long as you have some node.js skills, this should be very easy to set up. Just download it, edit the config file to your liking(the guide is right on the github page) and start postpromoter.js with node.

Here's a more detailed guide:

1. Download the code from the link above.
2. Rename config-example.json to config.json and configure it to your liking following the guide from the github page.
3. Download and setup node: https://nodejs.org/en/
4. Open up terminal if you are on a unix based machine(mac/linux) or the node.js command prompt if you are on windows
5. Type in cd into terminal and put a space. Then drag the folder with the files of the code into it. Press enter
6. Type in: node postpromoter.js then press enter.
7. The bidbot has been set up. Now test it by sending a bid to it from another account and then market it so everyone knows about it.