Cheap accommodation in Ostrava

Hello, should any of you have a tip for cheap accommodation in Ostrava for a longer period of time? I don't know it there, but I will have to be there for at least 3 weeks.
I found a cheap hostel Prodante.cz, which has a single room in the offer, which is ideal and for good money. But! I call a hostel in Ostrava if it's a good choice, what do you think?
Do not you have a better experience with an Airbnb or an apartment in Ostrava? The location is almost one, I will be a car.
 
Thanks in advance!