You asked

What lenses should I buy for the pentax k 500?

Here is what the site says about that.

From Pentax K-500: Pentax K-500: A DSLR by Pentax with a 16.3-megapixel APS-C sensor, announced in 2013. The K-50 without weather sealing. Specs - Maker: Pentax - Mount: Pentax K - Sensor: APS-C, 23.5 x 15.6mm, crop factor 1.5 - Resolution: 16.3 megapixels - Stabilisation: in the body - Announced: 2013 - Type: DSLR Focal lengths on it Lenses frame like 1.5 times their focal length on full frame: 16mm like 24mm, 23mm like 35mm, ...

From cst1 likes cameras: How to choose, in three questions: 1. What do you want to photograph? People, places, wildlife, sport, video, or a bit of everything on holiday. Pick your use case below and start there. 2. How much will you carry? The best camera is the one you take with you. A big kit that stays at home takes worse pictures than a pocket camera that comes along. 3. Which lenses will you want in two years? You ...

Quoted from this site's pages.

From these pages