Hi Kevin, I don’t have a room or couch to offer (just got here three days ago myself) but suggest you try www.loquo.com. Many affordable short-term rentals are listed there. Most are not hotels, but homestay/spare room/vacation crash sorts of arrangements. Lots of stuff for 20-70Euro/night and kitchens, etc.
The conference is the 3G.S.M. and is a cell phone thing. It’s around Plaza Espana, so avoid that area if you want to avoid the conference. Word is 50k people are coming and hotel rooms are going for upwards of Euro400.