There are so many of those hotel sites online ! But I've heard that Trivago is the best ! As far as extended stays? You'll have to contact them to see.
trivago.com - trivago Official Website
Where is a great place to find decent rates on hotels if I want to stay a week or longer? Are there inexpensive deals for extended stays?
This won't help but it's time for a story.
The cheapest accommodation I ever came across was at a function I was helping with about 25 years ago. Two French women decided to stay over an extra night and I had to collect some more money from the. They were dancing when I found them and one of them took me by the hand and led me into the dance.
She was a lovely woman made me realise that "light on her feet" was not just a cliche. It was like dancing with a cloud. She knew what I wanted and after a few minutes said, "How much do I owe for the extra night?"
"Well it was $40 when we started to dance, but it's getting less all the time."
"Ahh," she said, "you sound just like a Frenchman."
Unforgettable experience. :)