There are enough Bangkok hotels that are affordable with room rates around or under 25 dollar a night. If you're in for a party go the the Nana Hotel right next to the Nana party area. Convenient if you don't want your new "love" to walk a mile to the hotel. Hotels in Thailand are known for their service since staff is cheap to hire so even in the lower rated hotels you still get excellent service.

For an overview of all the hotels in Bangkok click here.
And for an overview of all the Hotels in Thailand click here.