Amazing promotion by American Express Travel Germany – get $22.60 (EUR 20) off any hotel booking – no minimum for these orders and no limit to how often you can use it.
Go to https://reise-services.americanexpress.de – you can use Google Chrome's automatic translation if you like.
Then input promo code jetztamex.
This hotel in Bangkok can be had for just 5 cents a night (the promo code also works on taxes and fees!)
Amex Travel Germany has very competitive prices for hotel bookings and their inventory is huge (much like expedia.com).
Book each night separately.
Do this now before the code expires.
UPDATE: You have to pay for any excess with an American Express card! You can either log in to your Amex account and pay from there, or you can continue without logging in but you still need to pay with an Amex card – it won't allow you to use a different card.