Anything around the price of a Rhino would be an old school no travel rail like mine, or a nice roller. You can't get a nice rail for the price of a Rhino without sacrificing something.....like safety, or quality of workmanship. IMO
Since your life depends on the quality (after all this is a dangerous sport) why go cheap?
You also need to consider replacement parts and availability. Possible repairs to the actual rail itself. I prefer to be able to talk to my builder face to face when these things come up.
You also need to consider how much power the sand robs from the drive train. Are you getting enough HP with your purchase. I think sandchick had a joyner, but found it was underpowered in the sand, but she had one of the older versions. Now they have one with a LS1. ...and their quality is lacking a lot.
Of course all of this is just my opinion....I'm sure others can add or take away from this. Just some things to think about.