I trued a few wheels up for a mate today. Two were on a 1990's Raleigh hybrid with Rigida wheels. These took five minutes each.
The other one was on a £75 BSO MTB. From new it had a 5mm buckle AND a 10mm "hump". Some of that was down to the badly fitted rim tape and the excess moulding on the tyre, but a lot was down to poor assembly of the wheel. What with poor nipple material, mis-sized spokes, and a badly formed rim, it took me over an hour to make an acceptable job of the back wheel.
I'd have been over the moon if I could have got that one done for £15!