5 places
A special and unique attraction is the 2 km monorail, affording views from five meters above the ground.
It's a little out of the center but worth the taxi ride. Lots of atmosphere and a nice place to just sit and watch it all happen.
The zoo is mostly tree covered and reasonably cool. Visit it on a weekday if you don't like crowds. The entrance fee is incredibly low (about 0.5 US Dollars).
The observation deck Saigon Skydeck (49th floor) is open daily from 9:30 AM to 9:30 PM for an entrance fee of 200,000 VND (about 9.00 USD) and offers a breathtaking view over the whole city.
The building is illuminated at night and looks very impressive. There is a nice little park in front of it where it's nice to hang out with the locals.