Chances are the bikes won't be too different. 80s and 90s(which the lower most likely is) are about as heavy as older cruisers, they might even basically use the same parts, sans drum brake. Murray was always a cheap bike and both are good deals and the older one despite 40 maybe being too high, especially since female bike are far more abundant, some scrooge could be asking $100 dollars just because it's vintage, regardless of it being a dept store bike and a womans bike. It was probably $40 new.
Other than that it could come down to condition; are they botg ride-away bikes or need something(s) fixed first, or if one or both has a standard size front wheel axle or not. If it comes to replace a front wheel and it has that old standard inch dia axle- which cheap 80s and early bikes often come with as well; a modern(mid 90s- current) 1¼ axle won't fit that fork.
If they both could be easily repaird without a co-op or bike shop consulting their clan elder, who then refers to the ancient Sheldon Brown grimoir to set an excursion to the basement catacombs, then it comes down to fit and looks.