With a day and a half I would be staying in town somewhere, I generally prefer around the Sukhumvit area. You can catch the Airport Express train to the City and then connect to a train to Asoke (otherwise a taxi is around $12 from airport to City). For less than $100 and if you want somewhere new & trendy, then the aLoft will do the trick. Loads of bars, restaurants in the same area. Terminal 21 shopping centres is not too far, cheap and good meals in the food court there, otherwise go all out and enjoy a tasing course at South East Asia's best restaurant, Nahm.
There's alot of hotel choices in the $100 price range so you could not go wrong with most really.