I'm looking for a preformed pan, 32"x60" that costs no more than $350. I had a National in my last house that seemed solid. The ones they sell at HD seem flimsy and light.

Without actually seeing and touching one, it's hard to make a purchase online but I value the knowledge from the posters here so I'll consider any recommendations.

Maybe the ones from HD require a mortar set base, that would make them solid. But you can check Lasco Bathtubs, and American Standard, check their web sites.

the plastic shower pans fron hd
are ok only IF. concrete is installed under them
mix 3.. 5 gal buckets of crete, mix it a little loose
dump out onto the floor, set the pan onto the mud and push down. hook up plumbing leval the pan, screw it to the wall.
let crete set up overnite. before stepping on it

Thanks for the tips. It seems there are basically 2 types - various forms of plastic and fiberglass or solid composite like Swanstone.

Depending on where you live, check in the yellow pages, make some phone calls, call a cultured marble dealer and/or a Corian dealer (two solid bases). I've worked with both. They can make a base, then you tile the walls, or they can do the whole thing complete.