About how much would it cost for a new roof on '91 LeBaron convertible?

I find the fabric piece to be from $339 to $539 and then you may need new cables ($29) and head-liner ($219), and Pads(???). Labor can very between locations dependent on how experienced they are on you car. I would think that it would run $300 to $500 to install.

In this answer I'm going to use some technical terms and I'll try to keep it simple and explain as I go. It takes a lot of extra engineering to design a convertible that drives well as apposed to a hard topped vehicle. Most modern automobiles are designed with uni body(also called unit body or monocoque) frame construction. This just means that the entire car including the floor, trunk, engine bay, firewall, A pillars, B pillars, C pillars, and roof are all a single flexing structural member and technically a solid part of the suspension. With a uni body vehicle the roof of a car has a large impact on the overall stiffness(or rigidity) of the car which affects the way the car drives, handles, and crash worthiness. If you just chopped the roof of of a modern car, the result would be a car that drives and handles very very badly ( imagine driving a piece of thin plywood) and wouldn't be safe in a crash. The overcome the side effects of taking away the roof a car has to be either be designed from the ground up to not need a roof or be redesigned and retrofitted with custom parts to add back stiffness lost when the roof was removed. That is where the extra cost comes in. It cost extra to design and build a car frame optimized to driving without a roof (ex: Honda S2000, BMW Z3). The alternative is designing a car with the roof in mind and retrofitting the frame at the production line for a convertible which is cheaper but produces a lesser handling car (ex: Chevy Cavalier Z24 convertible) and still cost more than producing a hard top car. Then there is the added cost of designing and building the specialized equipment for the retracting top and you start to see how convertibles can cost such a premium over their hard top derivatives. I hope this helps.