What is the best (and cheapest) way of hooking a laptop to a television?

I have a standard laptop and would like to hook it up to watch movies and videos on my 26” television. However I have found loads of different lead and am unsure which’ll do the job.

My mum has a lead that connects to her television, but my television doesn’t seem to have that port. I’m not sure what the port is called, but I should be able to identify it if you provide an image :).