Termas, La Bodeguita (LB) is on Calle Uruguay, downtown. It's a bar, it gets going late, often has live music, and freelancers hang out there. Quality is extremely variable -- everything from dogs to a few stunners. I wouldn't call it upmarket or downmarket -- it's in between. The other two places are in Casco Viejo and are bars/brothels. I've never been there so should let others comment, but atmosphere, quality and price should all be lower compared to LB. You're comparing very short time brothels (Casco Viejo) to a freelancer spot (LB) though.
Regarding hotels, Las Vegas and Hotel Ejecutivo would fit the bill. The Ejecutivo is nicer but charges $10 (could be more now) when you bring a date back, if they catch you. It might be above your price limit. I like Plaza Paitilla better than both, except as you should know the traffic between there and hot spots can be bad at times. It may be out of your price range now. I remember paying $40 or $50 there a few years ago, now it's $100+, but they have done work on the hotel. You asked about Montreal -- it's the worst of the bunch, cramped rooms with lousy beds (you get what you pay for), but they do have a decent rooftop pool, and hookers that use the place as a short time hotel and occasionally stop by the bar.