I recently wrote a tool to make my D&D games a little easier. It’s a web app that lets you load up an encounter’s worth of enemies and keep track of their health (plus extra stuff, like legendary actions). And it does the math for you, which is a huge weight off my mental load.
It would be neat to expand it with an API that lets you load in monsters from a database and calculate the encounter difficulty, but I’m in no hurry. I don’t usually have a lot of energy to code on weekends now that it’s my full time job.
$500/month = ~$125/week, but if you get two messages per week that’s $62.50/message. Still a lot of money though.