What can i use?

I want to add a nice piece of of wood (or something that resembles wood) in my cage for my ball to climb on any suggestions on a cheap way of doing this? i was thinking of going out side to get one but i feel like it may have harmful diseases or parasites that may effect the health of my snake.

Google "sand blasted vine". That would probably be the safest thing.

I personally think the chance of disease or parasites that could affect a ball python from collected wood have been greatly overstated. It it's a concern of yours I would fill up a plastic garbage can with a weak water and bleach solution, weight down the wood so that it stays submerged and leave it to soak for a few days. Rinse very well and allow it to dry for a good long time. If it still smells like bleach, let it air out longer.

Or just bake it in the oven at a low temperature (200-250) for a couple of hours. Avoid any wood from conifers.