I have 2 ladies traveling to Germany in late September and want to do 1 night in Heidelburg. They have a budget of $120.00. I found the Ibis Hotel that would work but after watching your video and you suggesting smaller more friendly properties, I thought you might have a suggestion. Thank you.
I will second the recommendation for the Hotel Hollander Hof. The staff is very helpful and welcoming. The rooms are clean and nice. It is in a fabulous location - right in the heart of the old town, along the river by the picturesque Old Bridge. There are restaurants, pubs nearby. Price may by just a bit higher than you desire, but for me the location trumps the difference. You should know that if you are driving, you will need to park your car in a garage a few blocks away.
Just so you know, this Rick Steves and his company do not answer questions on this forum. The general traveling public offers responses. There may be more than one Ibis in Heidelberg, but if you mean the one I'm thinking of, it sits right next to the Hauptbahnhof (main rail station). Not the worst neighborhood in town, but probably not where you want to stay. It's a considerable walk from the Altstadt. The only hotel where I have stayed in Heidelberg (before I moved to the region), was the Hotel Holländer Hof. It's location is right by the Theodor Heuss bridge spanning the Neckar. The cost might be a little above your budget, but not by much.