For hotel bookings we recommend the following options

Best Western Hotel Augusta

Ost am Kö Cityhotel

Ibis Augsburg Hauptbahnhof

Ibis Budget

IntercityHotel Augsburg

Stadthotel Augsburg

NinetyNine Augsburg

Cheaper but also recommended options (hostels) are:

Hostel Sleps: Single room 42€/night incl. breakfast), 59€/night as twin room incl. breakfast.

Slamba Hostel (single room 39€/night; double room 45€, 4-bed room 80€. also flats to share)

Jakoberhof City Hostel (single room 29€/night; double room 40€)