Congrats Gromit, its a nice feeling to be debt free (are we all 'really' debt free ?).
Many would say saving is'nt a good thing to do at the moment, practically zero interest rates at the moment and all that, but it does give you a couple of really nice options when there's a bit in the bank...
So you want a moderately expensive item. Normally you'd get it on the credit card, interest free loan etc etc...all potentially expensive. What i do is one of these two...
Buy it cash, then 'repay' myself and make sure the money goes back in the bank in instalments...in the same way you would to the loan agents...but no interest. I think of it as i'm my own lender. I take from the pot, but it goes back in.
Or, buy it on interest free..keep the money in the bank, and make sure the payments are made before the interest free period ends.
Either way, no interest. And if the worst happens (work wise) you always have the money you're saving in the bank to clear any outstanding 'debts'.