This thread is about Meia Praia, the suburb across the bay from Lagos, a town in the Western Algarve Region of Portugal.
I live in Meia Praia.
There is an excellent bus service operated by the local bus company Onda:
See these articles on my blog: http://bit.ly/dpo9IJ
There is no service after 20:00hrs except in July and August.
A hire car is advisable after this time. Alternatively, take a bus in before 20:00 and then cab back.
Also see: http://www.aonda.pt/