Replying to Cheap rails

while I'm waiting for the snow to fall I'm fixing/buying some new PVC rails. I went to Home Depot and realized their a lot of money. Does anyone know where to get some cheap rails? Also the largest they sell are 6 inch in diameter. Where do u get 10-12inch in diameter. I went by some pipe place that's about 10mins away from me and they charge you like 100$ for a 8inch in diameter. I asked them if they had any broken ones for cheap but they where still charging 80$ for a broken 10ft and 8inch in diameter pipe... Please help, thanks!