Another potential option is working at a university that offers free or discounted tuition for staff.
Personally, I spent a few years working at a job related to my undergrad (accounting/finance) and saved up enough money to fund a full time DIY post-bacc. I also moved to attend a university in an area with cheap cost of living. Though, I will say it was extremely difficult to walk away from a cushy salary and return to the frugal student lifestyle--but it's a necessary sacrifice if I truly want to be a physician. My biggest piece of advice is to sit down and pencil out your budget in detail to form a brutally realistic picture of your financial situation. Not just monthly expenses, but total cost of DIY post-bacc, study materials for MCAT, application/interview expenses, etc. Nothing about this process is cheap or easy, but it can be done with careful planning.