the first time i did a cassette release was for my band whose reach at the time extended as far as our small friend group of other musicians, and family. i found a free dual cassette deck on craigslist (a radio studio was getting rid of their outdated equipment that was sitting in a closet). we made 50 tapes, hand dubbed (real time lol), wrote on the cassette itself with paint marker, screen printed the covers (cardboard 0-cards), and glued them together. it’s a lot of work but it’s very rewarding. we did put them up for sale online but they rarely sold on there and the reason why we made the tapes in the first place was because we had a string of shows coming up, and then later did a small weekend tour with friends. i think playing shows is the best way to get your music out there if you’re still building an internet base and also the best reason to make a physical release at that stage. you have to start somewhere… usually there is a startup cost but cassettes are very forgiving and the price is not too high. it took a long time to sell those 50 tapes but having them and sharing them was more valuable than making a profit.
if finding a cheap deck isn’t working, you can buy 50 dubbed cassettes with DIY packaging on duplication.ca for $100, which is probably what you would end up spending anyway, if not more for a deck. and with all old machines calibration is always something to be weary of (your tape will get dubbed too fast or too slow). as fun as it is to DIY the entire project, you don’t really end up saving that much, especially accounting for the time it takes. i would skip the deck maybe unless you can find one for free and just order plain dubbed cassettes and make the rest an art project.
have fun 
and i hope that helped a little
