Comparable Service?? Not in the way AMA does in all ways. However United Modelers of America, Ltd. offers simple basic One Million Yankee Dollars Primary Liability Insurance for $38 per year. No magazine, no newsletter, just liability insurance for your damages to others. No way to guarantee they could cover their liability to you.
No contest thingies or whatever, but a very simple Safety Code which could, IMO, be a model for AMA, except that would make AMA dues around $100.oo with all the other services.

http://www.unitedmodelers.com/


Check it out for yourself. You have to define your own comparable.

HC UMA #7160