Our Vivaro was £4k (no vat) 3 years ago, on a 06 plate. Has done nearly 120k now though so will need replacing soon, will probably go down the brand new route.
Great van, no complaints, it just sailed through its MOT! It did have a new gearbox 2 years ago at a cost of £900 though but that wouldn't deter me from buying another.
Insurance wise I now pay £62 per month for 2 of us (I've got 6 points and 4 years NCB). Last year our insurance was £125 per month.
650 litre tank fits in nicely and keeps the 2 of us working for 6+ hours (when I've sorted the leak on my reel)!