The train timetable is exactly as indicated on the CP Website.
The fare per person will be a minimum of €19,50 per person. You will need to add to that the cost a taxi from Faro Airport to Faro Station. If there are two of you you will therefore have to budget an extra £ 50 pounds at least to get to Lisbon.
The alternative by hire car one way would be doable. Based, for example, on website quotes thru http://www.autocarhire.net, a 24 hours one-way rental would be a minimum of €116.00 for a small Renault Clio.
