My bad--I should have address that to Byron--sorry. I don't buy Bimini's at West or WalMart--not quite as far in the boonies--but sometimes it seems like it!
Looking at the Taylor Made site, they have 7/8 Aluminum tubing, 3 bows, with plastic fittings and straps for support--no Sunbrella--and the cost for Tom Cat size would be about $500. That seems to be what West Marine carries.
A full camper back adds a lot to the boat--and we keep our sides on year around. In the summer, some days the sides come off, but at night, it keeps the bugs away--and is still a another full room.
Certainly SS frame costs a few dollars more than Aluminum, but a good SS frame is good for the life of the boat. This includes SS fittings, which will not fail, as sometimes the plastic fittings do. The major cost in a camper back is the fitting of the sides, all of the zippers, windows etc--all labor costs. It makes no difference it the base is aluminum or SS frame. Same with sewing--no difference if cheaper material or Sunbrella SeaMark. So a few dollars more for materials is not much in the long run.
If you just want a sun shade, and are not going to use it full time, then the cheaper aluminum and other cloth will work fine.