Hakone Hotel

I am looking for a conveinent midrange place to sleep in Hakone for the night. My budgt is about 150 USD for 2 per people (total).

Can anyone recomend somewhere to stay?

As long as bathing together is not important, try Hakone Lake Hotel.
View of Lake Ashi from the room (mine was Japanese tatami room w/toilet. Also offer western bed rooms w/full bath), large nature surrounding, evening/morning quiet stroll & bird watching, great Kaiseki dinner and buffet bf(much better than high end Tokyo hotels). Even though it is the farthest hotel from Yumoto, frequent direct bus (~every 20min.)takes only ~45min., if you are in a hurry. The Togendai rope way station & lake cruise ship port is just a few min. walk and you can ride as often as you like if you had the Hakone Free Pass.
http://www.hakone-lakehotel.com/english/englishindex.htm
I consider it to be a hidden gem(not listed on a normal hotel reservation sites) after staying at various places & onsens all over in Japan. But you may have a different priorities.