Well, you have a 15 day trial with TurboCAD. It's $130. No matter what, there will never be enough time to evaluate.
It sounds like you want to go on the very low end, which is fine. I would suggest SketchUp. IMO, you need to have something that has a massive amount of public support from the community and SketchUp is king. Autodesk products are great, but you are looking at thousands. Rhino is a great program, but it lacks the punch of a great international support system. Chief Architect is a mid-range program that has a low end product. They seem to have decent support.
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