> do basic maintenance (oil/filter, brakes, etc) yourself
Basic maintenance doesn't get you much of the way to $900/month anyway. An oil change is like $50-$100 depending on things, and most OEM service schedules have those once a year (unless you put on a lot of miles... but if you put on a lot of miles, it's unlikely that you can realistically forgo a car). Brakes cost more, but depending on how you drive, shouldn't be too frequent; and you really should be competent at brakes before maintaining them or you're likely to cause safety issues. An incompetent oil change my ruin your engine and as a result your pocketbook, but an incompetent brake servicing can result in no ability to stop which has much bigger life safety implications.
Basic maintenance doesn't get you much of the way to $900/month anyway. An oil change is like $50-$100 depending on things, and most OEM service schedules have those once a year (unless you put on a lot of miles... but if you put on a lot of miles, it's unlikely that you can realistically forgo a car). Brakes cost more, but depending on how you drive, shouldn't be too frequent; and you really should be competent at brakes before maintaining them or you're likely to cause safety issues. An incompetent oil change my ruin your engine and as a result your pocketbook, but an incompetent brake servicing can result in no ability to stop which has much bigger life safety implications.