Whilst I typically use Roll20, I hear really good things about Foundry VTT, and they're running 20% off for their 3rd anniversary, dropping it from $50 USD ($75~ AUD) to $40 USD ($60~ AUD). They tend to run the sale twice a year (May and Black Friday), 20% is the usual discount, so best time if you're looking for a different self-hosted VTT with perpetual license and updates going forward. FAQs at https://foundryvtt.com/article/faq/#purchasing
About the software: Foundry is a Virtual Table Top (VTT) software, lets you host and play Table Top RPGs (TTRPGs) such as Dungeons and Dragons (D&D), etc.
There is also guidance for how to set it up to run free via Oracle Cloud Infrastructure: https://foundryvtt.wiki/en/setup/hosting/always-free-oracle
I put on my wizard hat and robe