OK, honestly, in Korea, you can do no wrong when it comes to driving. People routinely run through red lights, pass in the wrong lanes, drive the incorrect way down one-way streets, make u-turns using the pedestrian cross walks... and the police look the other way.
But during the "summer beach season" you absolutely cannot swim in the beaches outside of the hours of 9am ~ 6pm. If you try, you will have several beach patrols run to you blowing whistles and yelling at you.
Why in a country that you can drive like a madman, can you not swim after 6pm? Any other place in the world would simply post a sign with something like 'swim at your own risk'.
And the Koreas take the summer beach season quite literally. That season is July and August. If you arrive June 30 or September 1, the beach will be very empty and there will be no beach patrols.
Unique Suggestions: If you go to the beach, plan on swimming or wading only during 9am ~ 6pm. You can stay at the beach 24 hours a day, but the beach patrols will not let you walk in the water past your knees.
There are motels in haeundae area that advertise themselves as hotels over the internet with some having expensive rates. the motels in the area could be rented out to as cheap as 25000 won in low season or at the start of autumn in september.
If you want to forego using the cheap (6000 won) going to busan from gimhae airport, absolutely do not take private cars offering taxi service. a regular taxi would get you to your hotel at around 18000 won in light traffic.
Although people will try their best to help you out and many approach you out of the blue while sitting in the subway or standing at a crossing, the fact that Koreans have a big lack of knowledge in any kind of foreign language might definitely cause a problem to you:
No English menus (even at many McDonald's, Burger King, etc.), no English signboards (except of course for the subway and designated tourist hot-spots), no English-speaking taxi-drivers (translation-service via intercom required)... it makes life slightly complicated, especially if you are looking for some less touristy and more Korean-style locations.
Unique Suggestions: Go to one of the many Tourist Information booths, get a good map and ask as many questions as possible.
The ladies at the TIs are usually very friendly and will mark you specific locations directly on the map.
If you like to go to somewhere specific, let them write down the address in Korean, so you simply need to show the taxi driver where you wanna go to.
Beware, however, that the taxi drivers usually know the various districts (GUs and DONGs) but are usually unable to find specific addresses (mainly due to the very confusing street system of Korea, which only postmen tend to understand). In this case, it might be best to let them drive you close to the spot you intend to go to (e.g. subway station) and ask your way through.
Fun Alternatives: a) Be adventurous and explore the places on foot and, in case of restaurants, just try to point on something that looks delicious to you.
b) Learn the Hangeul - the Korean alphabet. It's less difficult than it looks like but will help you a great deal.
For all you coffee drinkers, stay away from the fancy coffee shops unless you absolutely must have a fancy drink. You'll pay twice at Starbucks than you will at home (North America). If all you're looking for is a plain cup of joe, you'll find it for much cheaper at Dunkin Donuts.
Western style food and restaurants in Busan are very expensive, and not necessarily great quality for the price you pay. Food will cost the same or more than you would expect to pay at home. I recently went out for a burger and fries, and it cost me about 12,000W, or about $12 USD. Wow!
There are several sit down places in Busan: Bennigan's, TGIFridays, Outbacks, and so on. Expect to pay 15,000 to 20,000W per person at these places, if not more.
Unique Suggestions: Seek out some of the more inexpensive options. Pizza Hut and McDonald's aren't bad. You can get food there for about the same price as you would pay at home, but it's far less than at some of the other chains.
Fun Alternatives: If you're looking to save money, eat Korean food! There's lots of it available (literally thousands of restaurants) and it's pretty good stuff. If you aren't sure what to try, stick with galbi or bugolgi (pork and beef BBQ) and bap (cooked rice). Meals will come with side dishes for free. If you're a little nervous about randomly picking out food, pick up a Lonely Planet phrasebook and bring it along when you go out. The dishes are written in Korean, so you can just point to what you want.