For my last trip from Lisbon to Albufeira, I travelled with a Flixbus coach.
Economy fare: journey of about 2h45 for less than 10€, with 1 hand luggage and 1 luggage of 20kgs in hold included.
Advantages of the Flixbus solution compared to the train journey: more time options during the day and arrival in the centre of Albufeira and not at the more outlying Ferreiras station.
Departure from Lisbon-Oriente bus station, direct route with first stop in Albufeira.
Final stop: Faro.
For more information: https://fr.flixbus.be/voyages-car/lisbonne-albufeira