Residence Santa Croce
The hostel was only a 5-minute walk from the train station (although you do need to cross a bridge with lots of steps, so it can be challenging to get to with large baggage). The room was very clean and well-lit, and the staff left biscuits and tea by our beds. I shared with three other girls (randomly assigned), but the accommodation was still a bargain - approximately $35 each for the night. The staff was extremely helpful and supportive. The hostel also has a second location near Piazza San Marco, and the staff will typically personally escort travelers (by water taxi) to that second location. If you have a preference of where you stay, I'd recommend confirming at the time of booking.
From journal 24 hours in Venice, Italy