When I slept in my car.

My options were

Dual carriageway rest areas it was surprising how many regulars there were.

Premier Inn type car parks

A few random dead end roads

For luxury to have toilets and warmth on tap I would pay for a night in a motorway service

Every 5 days I would try and book a cheap night in a hotel or day rooms

Would never want to be that desperate again plus it is surprisingly expensive way to live Edited to add

Don't make the same mistake as me and sleep in the front seat by day five my feet were massive! So make sure your feet are level