import re
my_list = ['Prix TTC euros : 10,10', 'Prix HT euros 8,42', 'TVA (20.00%) euros : 1,68']
for item in my_list:
found = re.search(r'[-+]?\b(?!\d+(?:[,.]\d+)?%)\d+(?:[.,]\d+)?', item)
if found:
print(found.group())
aW1wb3J0IHJlCgpteV9saXN0ID0gWydQcml4IFRUQyBldXJvcyA6IDEwLDEwJywgJ1ByaXggSFQgZXVyb3MgOCw0MicsICdUVkEgKDIwLjAwJSkgZXVyb3MgOiAxLDY4J10KCmZvciBpdGVtIGluIG15X2xpc3Q6Cglmb3VuZCA9IHJlLnNlYXJjaChyJ1stK10/XGIoPyFcZCsoPzpbLC5dXGQrKT8lKVxkKyg/OlsuLF1cZCspPycsIGl0ZW0pCglpZiBmb3VuZDoKCQlwcmludChmb3VuZC5ncm91cCgpKQ==