This 50mm f1.7 for example:
This lens was never an expensive model, and this one was picked up for 15 whole British pounds. It came attached to most Pentax cameras produced in the '70s and '80s and has been a cheap 50mm ever since. However, this doesn't necessarily mean that it's a bad lens. In fact, results look more than okay:
|The standard Tintin test.|
|A kind of similar camera and lens?|
|A roughly equivalent camera and lens.|
It's also built like a tank: I dropped it on the hard ground in the shop (after buying it) and it didn't damage it at all. It's full metal, with the kind of smooth damped focussing that you only seem to get with old lenses.
And out in field conditions: