Telegram Bot that send you updates about stocks/etf/etc. supported by Alpha Vantage. They offfer a free tier API Key, so this is completely free.
Simply chat with the @MercatusBot
You can host it yourself of course. You will need a server.
wget https://raw.githubusercontent.com/cupcakearmy/mercatus/master/docker-compose.yml
# Set your own telegram bot token
vim docker-compose.yml
docker-compose up -d
git clone https://github.com/cupcakearmy/mercatus
# Insert the variables found in the docker-compose.yml file with your token
touch .env
vim .env
docker-compose -f docker-compose.dev.yml up -d