Ask for a seat on the emergency exit row, where there is more leg room and the seat ahead of you doesn't recline as much. But Hostels are a great place to meet other travelers and share the latest and most accurate travel info. However, there are other accommodations. Cheap hotels are another alternative, but be careful where they are located. Many are located in less desirable areas, although OK if you take normal precautions.
Camping is an alternative worth considering.
It is definitely cheap and there are many formal camp grounds. The quality vary greatly. There are also unofficial camp grounds, often ignored by the local police. Camp sites offer little security. Typically, it is unwise to sleep in city parks, unless they are officially designated for such.