Think about how much any professional pays to a tutor or coach to learn their craft. Many pay thousands, even tens of thousands. In comparison, spending just over a grand to learn a life skill like driving isn't that much. Besides, you don't pay it all at once. If I told you that your annual supermarket / grocery bill ends up more than a thousand pounds over the year, you'd be horrified, but you only spend it in bits every few days or every week. Driving lessons are no different. Pay weekly, or in chunks per month to get discounts, but look no further than that.
If you're comfortable with your weekly / monthly outlay, then carry on as you are, and you'll pass your test when you're ready, however long it takes.