Is $2,500 to install a Liberty 3 ply roofing system a fair price?

I have a 10x10 area of roof over my back porch that has a very low slope. It was done with shingles by the previous owner which has caused a lot of water pooling and rot. I live in a cold/snowy environment and I'm unsure if that will affect the opinion. The area is connected to a shingles roof that is at an appropriate slip, I won't be replacing those shingles just yet but will likely stick with shingles going forward.