Where to stay while in Amsterdam?

My boyfriend and I will be in Amsterdam for two nights, arrive 8/6 and check out 8/8. We want a clean cheap place to stay. Hostels are fine as long as our room is private. We are willing to have a shared toilet and shower though. And we want to be very near the city center. Being able to get there by foot or bike easily is what we really want if the hotel/hostel is not already located centrally. Your suggestions are greatly appreciated! Even the junkiest of places seem really expensive from what I have found....We are looking to spend 100 dollars a night or so. If that's even possible haha