How to check if camera and lense are ok?

I'm buying a nikon d3100 but second hand… With 18-55mm lense. I'm getting second hand because its more in my price range and i wi probably upgrade in a few months.
I'm going to look at the camera this week and i don't want to buy something not worth my money. Are thete any ways i can check if lens and camera are good? Anyone have a checklist?

Take a few photos with it before you buy. The word is "lens", not "lense".

There's a check list but it requires some brainpower

1. Check exterior condition including front element of lens
2. Chat with seller, figure out why it's going
3. Check workings (focus, flash, zoom)
4. Look into the lens to check aperture blades and condition
5. Shoot a few pictures and examine them closely
6. If it doesn't feel right at any stage, apologize and walk away

Jeroen is correct. You'll be upgrading in a few months? That's stupid. Keep the D3100 for several years and buy new glass, not a new body.