Unfortunatly, the only way to learn really is to push too far, which means spins etc and if your on the road, crashes.

If you never or rarely do, your not pushing very hard, which means you wont learn fuck all.

IMO its actually cheaper (due to not have to keep paying to sort out smashed bits) to shell out for practice days.
80quid and hours and hours of decent practice time is better VFM than what 80quid will get you on the road, which is a bit of petrol, a few crappy roundabouts, and the repair to your bent steering/suspension arms.

And this is talking from experience.

Streets ok for dicking about on when you better, but for learning, its not really VFM.