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$400 wouldn't even be a deposit in my world.....
Mine is 4.5 years old. Feel free to take a look at my link below for pictures. Mine is the 4000 model, no stereo. http://mccallw.tripod.com/spa.html
Dynasty are a very low end quality spa, but for $400 if it is working is not a bad way to get into tubbing.I would ask to see it running first, also they commonly leak and those repairs will get expensive.
The one I'm looking at is the same color as yours but it doesn't have the lounger but other than that it's almost indentical. How do you like it after 4.5 years and have you had any problems with it?