I had to buy a replacement drum unit in 2016, that was $22.59 (third party, of course).
I find it unlikely that an open-source DIY printer is going to result in something better or cheaper than what I've got.
The situation that always seems to happen to me is I need a printer ASAP. When shopping, I might find support for the Brother HL-2270DW in linux, but my local store might have a "Brother HL-2275DW" in stock (made up model number). So I'm wondering if the driver for the 2270 will work on the 2275, etc.