That depends how you calculate it...
I bought a cheap 4 bedroom house (in great condition, working-class low-crime neighborhood... really good deal) and rent out the other 3 rooms for $850 total... after $506 mortgage payment (includes principal, interest, taxes, insurance) that leaves $344 for maintenance, vacancy, and other house-related expenses.... so I really consider myself as living here for free :)
We split utilities 4-ways (including internet) which makes it about $40/month for me altogether... add in food at about $200/month (I do eat a lot... active lifestyle and all... this also includes some commercial beer and costs for my homemade hard cider) and my primary living expenses (food, shelter, utilities) are just under 3k.
Transportation by bike... health care is free through my dad's work until I turn 26 in a little under 2 years, then I'll probably get a free or nearly-free plan through the exchange thanks to the ACA subsidy.
Cell phone will soon be free through freedompop (once they get around to shipping my phone...) with plenty of minutes/texts/data for me.
I could probably throw in another $1000/year for extra 'stuff' and live quite happily for $4k/year. Hard to say what it'll really end up averaging long-term since I only finished college a year ago and bought the house a few months ago (lived with my parents while waiting for the right house to come on the market and getting started on my online job)... but I can't imagine spending more than $6k/yr or so even if I lose my Mustachian edge.
Shooting for a $10k/yr from 4% SWR, and having the house paid off before I retire... since that's what it'd take for me to feel secure about it.
Note that I'm not including student loan payments as expenses... the bulk of them I probably won't have to pay due to the pay-as-you-earn program (currently $0/month, only goes higher if my AGI goes above 18k or so, and whatever's left is forgiven after 20 years), and the other loan which isn't eligible is almost done paying off.