150โฌ will net you a stay in most countries in the EU except scandinavia and too big cities.
For 150โฌ a day, Budapest, Warsaw, Split, Prague, Vilnius, Salamanca, etc.
Be mindful of where you rent, make sure to have travellers insurance, don't get scammed for BS reasons (like peeps trying to make you believe you need to pay high money to use the autobahn in Czechia). Be mindful of pickpockets anywhere southwest of Paris and enjoy the food and locals.