Greetings!
Well, for what it's worth, my total living expenses for 2013 were $5300, and I do a lot of traveling, and a lot of eating out.
That included enjoying life to the fullest and not trying to scrimp or scrounge. That figure included about 30k miles and a brake job.
My humble advice is to buy a CHEAP old van, mine's an '82, that's mechanically sound. The newer the vehicle is, and the higher the value, there is more to go wrong and the maintenance costs will be higher.
If you're not going to be hauling really big/heavy loads, I would suggest a full size van with a v6 in it. A friend of mine has an almost identical rig to mine except his is a 1986 Dodge 15 passenger window van with the high top. The difference is that his has a 3.0L v6 fuel injected engine coupled to a 4 speed automatic with overdrive. When the time comes, that's what I'm going to replace my 318 with... Anyway, he is involved with disaster relief and regularly pulls a 8x20 office trailer all over the country with it, and still says he averages 25 MPG, which is better than I get with no trailer.
I drove that rig from Aberdeen WA to New Orleans for him when Katrina hit, and it had at least as much power as mine does, and it pulled that trailer like it wasn't even there... I was impressed, and that isn't easy.
He's got a full camper van load similar to mine, plus a stinger tray which carries 6x 55 gallon full drums. I think just the weight on the stinger must be over a ton.
I don't know what area you're in, but I regularly see old vans and even old motorhomes on CL for under $1,000. The guy I'm currently helping in my off hours just purchased an old 40' bookmobile for $600 off CL. It ran and drove great, and was even mostly livable. We wound up trading it straight across for an old school bus though, because after he had it, he decided he wanted windows. In just the last 2 days we have it almost completely furnished for free by shopping CL's free section. I figure I can build his electrical, plumbing, heating, and cooling systems for under about $500 total. My goal is to get this homeless family of 5 totally moved in and comfortable within the week. Once completed, we're going to move it to an RV Park, and I'm going to pre-pay their rent for a year for them to give them the hand-up that they need to get back on their feet.
Anyway, the point I'm trying to get across here is that you can have a very comfortable living quarters, in virtually any size you want, for a relatively small amount of money. I tend to think of my homes as disposable, because you never know if you might need to replace it, and by keeping them cheap, they're also cheaper to replace.
Being a mobile traveller makes us much more susceptible to losing our homes due to collisions, theft, weather related catastrophes etc; so the lower the cost of your home, the easier they are to replace.
I can take any van, and turn it into a comfortable living space, for under $300, with a trip to a thrift store, a trip to Walmart, and if there's a dollar store handy probably save an additional $50 on top of that. I guess I'm kind of a 3 hour homesteader kind of guy. Once I have a van, I want it to be move in ready within about 3 hours. And I'm not talking about bare bones survival here either. I'm talking about living comfortably, with a good bed, a bathroom with a shower, a kitchen, and at least one good comfortable chair, and I'm not talking about the front seats either.
I typically do this two or three times a year, because in my business I may have to be on the other side of the country the next day. So I'll park this van in an RV park where I figure it will be safe in my absence, and jump a plane. A few months ago when I had to fly back to GM, I hit town just before 3pm, had a van bought, outfitted, moved into, and started cooking my dinner at 7:30pm. Bought the first POS rust bucket van I saw for $350, because I really didn't care what it looked like, it drove good. Now GM was paying me $1,000 week for living expenses (motel, food, rental car, etc.) Me, I had just over $600 in my new mobile home, including the first weeks worth of groceries. It was funny, I had the ugliest vehicle in their whole parking lot. The job wound up lasting almost a month, with me working mostly 18 hour days... It was perfect, when I would get off work all tired, my comfy home was waiting in the parking lot.
By the end of the job, I had made over $3000 extra in living expenses than what I had put into everything, and I was a whole lot more comfortable than I would have ever been in a motel. The job was over, so I headed down to the local homeless shelter, and found a young couple with a 3 month old baby. I took them out to this pathetically UGLY van, and gave them the tour of the inside and asked if it would help them out. You would of thought I was the Angel Gabriel himself. So I gave it to them, free and clear, and they drove me to the airport. I didn't tell them, but I left them an envelope with that $3000 extra I had gotten for living expenses too. I felt it would be appropriate for it to get used for what it was meant for, even if it wasn't me using it.
Vandwellers are blessed with the ability to live extremely cheaply, without having to compromise on their comfort. I think the secret is to think outside the box, and rather than buying an expensive overpriced premade camper van, start with a cheap empty van and build it to suit your own personal needs and comforts. Once you move in, you have just eliminated the expenses of rent/mortgages, utility bills, and property taxes. If you're cutting the number of people you're feeding, your food bill will drop too. Your expenditures on vehicle insurance/maintenance, cell phone, etc. etc. will be the same as they have always been. The only things that will cost you a little extra might be wifi, and a little propane or kerosene.
Good luck, and holler if I can be of assistance.
Cheers!
The CamperVan_Man