Andorra is a little country between Spain and France, completely independent and tax free, coach is not the cheapest of options but I do enjoy the scenery (and it can be quite a long day ahead).
BARCELONA TO ANDORRA DAY TRIP
3 hours from Sants Estació (Metro L3), come out and find the coaches section.
Eurolines has a counter there, you can buy online too. (beware of pickpocketers in Barcelona's coach station).
You must check in at the counter before travelling.
Best season: unless you are a ski fan, I enjoy it better in August, hotel rooms are cheaper, coaches are rather empty, and they have a night show in Caldea.
Distance: 3 hours from Barcelona, regular daily coaches.
The streets are full of shops with perfumes, watches, sunglasses, tobacco, biker's gear, chocolate, etc.