There is a Sheraton, but no Westin in HCMC. Sheraton/Park Hyatt will run $150++ at least. Sommerset near the French Consulate is nice. The other is a bit run down.

For $100 or less, check out the Duxton on Nguyen Hue. Haven't stayed there, but hear good things. You might also check out Indochine. I've heard nothing but good things about it and the price is very reasonable. Location is good with many good restaurants within a 5 minute walk (next door to the best Thai restaurant in HCMC IMO).

http://www.indochinehotel.com