Around that get cheap housing or do I just sleep In the streets with a knife for safety
Sleeping on the streets is quite unusual in many places in Europe and it is likely to get you picked up by the police. Traveling with a knife is completely unacceptable. Suggesting that it might be possible to do those things shows that you don't really have an understanding of what traveling in Europe is like, and that's OK. Just do lots of research before you get there so you don't land yourself into trouble. Here are some websites though that can help you travel cheaply:
couchsurfing.org
wwoof.net
airbnb.com
hostelworld.com
homestay.com
wikitravel.com
crewfinders.net
It is possible to live a nomadic life in Europe on a budget, but don't expect to be able to make much money on the way. In some places like Spain you could potentially find work under the table tutoring English, but without contacts in the region this can prove difficult. Make sure you know your EU countries and Shengen Zones so you don't overstay your permitted amount of time and get deported to your home country on your expense. This makes future travel more difficult.
People like smart travelers, but hate idiot tourists. I would advise you to take care as to which side of the fence you land.
Many years ago this was possible, but not now. Just what do you intend to do for money? If you are not an EU citizen you cannot work and, due to the large number of Europeans willing to work legally for low pay, no employer will risk employing a foreigner illegally.
You need to be aware of the Schengen Zone rules - 90 days in and 90 days out of the Zone in any 180 day period. If you overstay you will be an illegal alien so, anything that brings you to the attention of the authorities eg emergency medical treatment, police checks, using that knife, will result in you bring charged as an illegal, deported, and banned from the EU. BTW it is illegal to carry a knife in Europe.
A condition of entering any country these days is that you have enough money to support yourself in reasonable comfort. If you look shabby, try to work, are found sleeping rough, you will be charged and deported.
Well, good luck to you. Remember to bring extra socks!
Zafir nails it.