need ear buds for iPhone 5c

You can purchase them in the online store, an Apple Store, and there are many other retailers that carry them. I know here in the US we can get them at Walmart, Best Buy, and a few others.

if you don't need a mic and the buttons

any headset since the first walkman from sony in 1983 will work

it's called minijack 3.5mm connector and is used for computers and most other devices