Mercure, one of the nicest budget hotel in Bangkok with a nice view, cost about 1500 THB for a double occupancy room with a king size bed.
If you walk in to the hotel, then it might cost you double, so better book it online, they always have some offer running, also you can get 1+1 Cocktail at the bar too, which is pretty fair and moderate as compared to the other hotels.
It has a nice pool with a view of skyscrapers by both sides and a highway view in the front.
The hotel has 19 floors in total, The top two being the most luxurious and offering a extended balcony and the pool is on the 10th floor so you get a pretty epic view from there while chilling or just taking a dip.
The food is also moderately priced, You can easily fill your tunny with a 300THB meal.