Where would I find the cheapest way to travel from Rome to Barcelona and Barcelona to Paris? Please help ASAP?

Hi everyone! I'm only a college student and I'm planning on a European trip with my friend and I. So far we are traveling by plane which is costing us a fortune but I was just wondering if there is any easier way to travel around. If so can I have a legitiment website or direction to where I would find it? Thanks.Where would I find the cheapest way to travel from Rome to Barcelona and Barcelona to Paris? Please help ASAP?Go ask a travel agent, duh!Where would I find the cheapest way to travel from Rome to Barcelona and Barcelona to Paris? Please help ASAP?research trains and buses