I don't know how much time I spend in the garden - I do know there are lots of other things that need doing, that aren't getting done at the moment! I love having the time outdoors and noticing all the wildlife, whether it's the birds (red kites, robins, magpies, starlings) or the micro-wildlife that is really fascinating me lately - damsel flies, beetles, spiders - so much of it there when you look. Plus I'm stronger and fitter than I was before I started the garden. As for money - this year will be relatively expensive, as I'm starting out; had to buy tools, lots of compost, seeds, etc etc. But even there I did it cheaply; got a water butt via a Freecycling friend, a fork for £3 from a house clearance shop; used reclaimed wood to edge my beds, acquired plastic for nothing, to use for my cloches; and got lots of seeds via swaps here! :)
In terms of costing food - everything I grow is organic, I know there isn't any chemical residue on it (other than whatever is in the air, generally, in Reading!) - so I'd be comparing against fancy-schmancy organic grocery prices. We eat a LOT of greens, and spinach is expensive to buy. Some of what we're eating now, you probably can't buy even if you wanted to - eg Red Mustard Leaf and chard.
There are so many good points - the only bad one, as I said, is that I'm neglecting other things in life which have rather been pushed to the back. I'm creating this garden from scratch, so that's my excuse. Next year will be much easier, I won't have to dig beds from couch grass. :)