To those of you who have done a dual battery set up or researched it, how much does it cost? Is the Traxide kit still the go to?

 

The real question is do you want a pre-fab kit or are you willing to roll your own? If you want a kit like the Traxide it will cost significantly more but should be easy. If you're willing to do it yourself you should be able to do it for less than $100 + the battery itself.

The simplest thing is to just use something like a Blue Seas ACR. You could also build your own system pretty simply by just using a continuous duty solinoid that is only energized when the ignition is on. That's about as basic as it gets, and prevents any accidental discharge of the starting battery by the house loads.

There's a ton of info over on ExPo in the '$50 dual battery' thread, right down to part numbers to DIY.

How to make a cheap isolated dual-battery setup for $50 - Expedition Portal

 

I purchased the National Luna set up.I have had it for about a year and love it.