Few variables here.
What is your budget? I think sub £100, Nudie are up there although I think for that money, Edwin are better constructed. For prewashed denim, Nudie have a pretty wide ranging line, esp in Grim Tim and Thin Finn. Edwin not so big but still a safe bet.
If you're open to the concept of raw denim then a little over a ton will get you a pair of Edwin Sen Selvage which are a good fit and age pretty well for an entry/mid level raw denim jean. The same can be said for APC- the new standard, petit standard and new cure are all worth a look.
If you're wanting to step it up a gear I'd suggest looking at Momotaro, (their budget colab with Japan Blue are also good) and maybe Studio d'Artisan and Pure Blue Japan.