Just to clarify......do you want 1" ID pipe? or 1" OD pipe (which would be a 3/4" line)
Where in TN are you? I dont know how far south menards has expanded, but they can get alot of that black pipe, and best prices I found when shopping for geothermal piping. Just have to decide on what side you want.
1" SIDR 7 pipe is 250 psi rated, and 1.349" OD , 1.049" OD..............$212......400'
1" SIDR 9 pipe is 200 psi rated, and 1.283" OD , 1.049" ID............$153.........400'
1" CTS in SDR 9 is 250 PSI rated, 1.125" OD, 0.875" ID.................$153........400'
3/4" SIDR 7....250PSI ......1.060" OD.....0.824" ID....................$97-300'.....$178-500'
3/4" SIDR 9....200PSI.......1.008" OD.....0.824" ID....................$73.......400'
3/4" CTS....SDR 9...250PSI....0.875" OD.....0.681 ID................$93.......400'
And whatever you get, I think you are going to have a hard time trying to shove it through 3" drain pipe. Which I think is not needed anyway.