Advice on finding cheap bus/train tickets through europe.
Hello fellow travelers. I'm planning to go to poland this christmas to see my family (I live in spain). I did so last year with cheap plane tickets I found, however, having to fly caused a severe anxiety that lasted for a month before the flight and my whole visit (I am aerophobic, usually I travel with a family member or a friend, but now i'm an adult and with no reassurance when solo traveling i usually have panic attacks). Therefore; I have decided to go with either train or bus. I've never went to somwhere that far though, and the pages to book tickets get too confusing. I also have no experience finding good deals.
Does anyone here who is more experienced than me in this can advise me on how to find a good deal? It doesn't have to be fast, just cheap.