With SKM, the commuter train, it's really easy and quick and cheap to get to both Sopot and Gdynia. AND get off the train at Gdansk Wizeszcz for shopping at galeria baltycka.

wanna go to a cheap club/hotel?
head for Do Studzienki Street where student's houses are - on lower floors are cheap bars/clubs and over not very epensive rooms (especially during the summer)

Great city with plenty of history and historical monuments to see...restaurants and cafes ...and of course alot of boutiques ....all for a very good price just for you...

Go to the maritime museum it's really good value and allow at least half a day

If you're looking to buy amber, Gdansk is a great place to do it.  You'll find it in Krakow as well, but it's generally a bit cheaper in the north.

The July-ish Opera Festival should not be missed, there's only one choice of beer to drink, but by the end of the weekend it's fairly cheap to come by. Lots of fun also to be had at the beach. But bring extra blankets, as it gets quite chilly at night.