I have not found any self hosted solutions (paid or free / open source) and I've looked a lot in the past. I've seen services like Drip and ConvertKit offer this but both of them are at the high end of hosting costs. To put things into perspective it's $80 / month for a list of 3,000 users with ConvertKit even if you send nothing.
One of the more polished tools I've seen is Freecodecamp's https://github.com/freeCodeCamp/mail-for-good project but it doesn't support auto responders or tagging. I've opened issues on this 2+ years ago at https://github.com/freeCodeCamp/mail-for-good/issues/196 and https://github.com/freeCodeCamp/mail-for-good/issues/197 but I don't think they are going to implement it.
ConvertKits is expensive - all plans fall under BigMailer's free plan :-o
I was hoping to find a 1 time purchase solution that meets those requirements. Sorry for not being more clear in my description.