My sister has a 6-hour layover in Lisbon this weekend. She is looking for a private service to pick her (and her luggage) up at the airport, take her to a few sites in the city, and drop her back at the airport a few hours later to catch her next flight. She is a solo traveler, so she needs to keep costs down (preferably $150 or less). She had made arrangements but the company canceled on her last minute, so she asked for my help finding something else, and you folks are the first I thought of to assist!
Can anyone recommend a reliable and trustworthy tour guide who will pick up / drop off at the airport?