At this end of the market, mileage shouldn't be so much of a concern. It's more about how well it's been looked after. Buy on condition, not miles. My Passat was bought on 145,000 miles and barring the rear brake pipes, and a couple services, hasn't needed a penny spent in 2 years / 20k. Before that I bought a Polo SDI (so no fancy injectors / turbo / clutch to worry about) on, again, 145k miles. Banged 10k on it, using 50/50 mix of vegetable oil and diesel, and never needed a penny spent.
I would be looking more at cars with 110k or more on them, with evidence of recent work having been done. Cars approaching 100k often do need work doing, such as the clutch, so buying just short of here might mean you have to do this work. Buy a car over 100k, and this work is more likely to have been done already.
Or else your looking at cars with 50k on them, but at your budget, that means they have either spent their life doing short journeys in town, or sitting doing nothing. Neither is good realistically.