I'm buying a bike/scooter 125cc, what would be considered high or low mileage?

I'm looking to purchase a Honda CBF, Honda CBR, Aprilla RS, Yamaha YBR or Yamaha YZF… Any recommendations?

Anyway, to the main point! I was wondering what a high mileage for a 125cc scooter/motorbike would be? And how old of a mototbike I should get?

I understand that it depends on how the person has looked after the bike etc however, what would be considered a high mileage, low mileage and medium mileage?

Well the Jap 4 strokes will pretty much go on forever if they're well maintained. I've seen some used as commuter bikes with in excess of 40k miles. With regard to the two strokes like the Aprilia RS I'd personally avoid anything with over 15K miles unless it's had a recent top end rebuild.