Looking for a decent inexpensive hotel to stay at near Soldier Field.
Is there a reason you need to stay by Soldier Field? You have a much bigger selection should you decide to stay somewhere with good access to transportation to Soldier Field rather than stay near Soldier Field. In addition to the ones mentioned, there's a Best Western Grant Park that has OK reviews. Personally if I had to find a room in Chicago, I'd try to use Priceline or Hotwire and use the bus or el to get to Soldier Field since most of the hotels are a mile or two north of it. Or I'd have a look at Air BNB.
Try the Hilton on Michigan Ave or the Palmer House Hilton and Congress hotel both in the Loop. There's always Air BnB too.