Is it cheaper to buy notebooks than write in them?

There's a bit of a credit crunch on at the moment. I don't know if you've noticed?
So as a result I've been trying to cut back on my spending. There are several things that I spend money on that I don't really need to. I've found lunchtime when I actually get away from my desk the time tht can cost the most unnecessary expenditure.
Making sure I take my lunch items with me each day is really helping but one of my occasional lunchtime pleasures is going out to look at notebooks. As you can see I sometimes buy one. Now I have to admit I've been too busy for this pursuit lately and so that has kept me from wandering and spending but I was thinking perhaps this is cheaper than if I actually wrote in the notebooks.
Why?
Well If I wrote in the notebooks I'd have to go out at lunchtime and find a spot to sit and write. Now if you're from Scotland you'll understand, it is invariably windy, wet, cold, baltic, snowing, basically inclement. So sitting on a park bench is a once a year summer treat. The rest of the year I'd have to go into a coffee shop to write in my notebook. Average cup of coffee in local cafes is £2.50 I'd say. And I'd have to buy that everytime I went in. It's not the same as going looking at notebooks and sometimes buying one. Okay a notebook purcase could be equivalent to two or three coffee shop visits but I still think if I got into the habit of a lunchtime coffee while I filled up all my existing notebooks then that would spend more money.

So the result of this is that while I bring my lunch in with me as part of my money saving campaign i can also go and browse through the stationary departments and maybe even buy a notebook every now and then...... Result