Смотрим HTML через, например, Chrome DevTools:
Читаем в документации к BeautifulSoup 4 (раздел
"Entities" ):
An incoming HTML or XML entity is always converted into the corresponding Unicode character.
>>> from urllib.request import urlopen
>>> from bs4 import BeautifulSoup
>>> html = urlopen('https://beton24.ru/sochi/beton/')
>>> bs = BeautifulSoup(html.read(), 'lxml')
>>> result = bs.findAll("span", "catalog-index__link-text")[1]
>>> result.text.replace(u'\xa0',' ').replace(u'\u2009', '')
'от 3836 ₽'