St. Petersburg, Florida is located on a peninsula between Tampa Bay and the Gulf of Mexico. The museum district is home to several of the top museums in the city. There are plenty of historical buildings and structures and even some ghostly tours of the different places.
The Sunken Gardens are one of the must see sites while in St. Petersburg. Not only are there over 50,000 plant varieties, but there are also alligator wrestling shows for some lively entertainment. St Petersburg Pier offers shopping, adventure activities, and even a small aquarium. You can also tour the HMS Bounty which has been used to film several major motion pictures.
The climate in St. Petersburg has brought about the label, "The Sunshine City." There is an average of 360 days of sunshine during most years. The temperature is relatively even all year long. The highs don't get much beyond 80F and the lows stay around 50F. The weather is a large draw for northern tourists during the freezing winter months that they have to deal with.
There are plenty of cheap flights to St. Petersburg available through many different sources. You can find cheap airline tickets from New York to St. Petersburg International Airport (PIE) starting around $150 US. Flying in from Los Angeles, you can find cheap airline tickets starting around $200 US.
You can find accommodations around the city that will fit every taste, need and budget. There are plenty of cheap hotels in St. Petersburg with rooms starting just about $100 US. If you are willing to stay a little off the beaten path, there are cheap hotel rooms available for just over $50 US.