arriving in june

We will be arriving in Hanoi around mid June. Is it difficult finding inexpensive rooms($15.00-$20.00) without reservations at that time? We will be traveling via train to Hue, Nha Trang and on to Saigon. Would we find it difficult obtaining inexpensive lodging in any of these cities during the June/July period? I see many hotel rooms priced as to high season and low season. When are the low and high seasons and why?

When I talked with a tour guide, she said the high season is in August and December when westerners have a longer holiday and they go to SEA, but a regular poster here (hanno) said a different timing. My personal experience is to book a hotel in advance if my flight is late and I arrive in a new city in late evening, other than that I just walk around, check out some hotels and agree on price. Maybe you get a list of some good hotels recommended by TTers and go there then decide where to stay.

If you have never been to Hanoi before i would advise booking your 1st night before you go and getting the hotel to pick you up from the airport.
i usually stay at the Classic 1 in Ta hien st about 50mts from the beer hoi corner