Hostel - you normally hv to share room/bathroom with stangers

although some hostels may have individual room with bath, but that are exceptions not the norm. And if you go for that type, they are not much cheaper than a B&B.

If you are willing to share room with 3 or 5 other strangers and sleep on bunkbed, (may need to bring your own sheets), also share bathroom, then hostel would save you money.

But you can also find B&B with shared bathroom and still have your own room, that is not much more than hostel.