Hi Rob,
We recently stayed at Centrepoint Silom which I highly recommend for a 2 week stay.
You can get a huge one bedroom apartment with kitchen and laundry facilities within your price range. It will be much ,more comfortable than cramming yourself into a hotel room for 2 weeks. The room has an audio system and DVD player and if your work is anywhere near a skytrain station it would be ideal as the nearest station is less than a 5 minute stroll. It is on the river and on top of a department store, next to a night market and has a reasonable breakfast, great pool and gym.
For a weekend getaway, you can fly to Phuket or Krabi for under $100 return with Air Asia and go to much better beaches than you would experience at Pattaya, but if you dont want to fly, I would recommend HuA Hin as the beach there is better and water more swimmable as Pattaya bay is polluted. You can get there in a little over 2 hours by road.

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