Drain Pipe Solid
http://www.lowes.com/pd_24160-1814-S/M+06004++0600___?productId=3133159&pl=1&Ntt=4%22+drain+pipe+cap+styrene $13.98. Then 10% off when buy 10 ($12.58). Then 5% with Lowes card ($11.95). Then 10% HomeDepot match ($10.75).
http://www.homedepot.com/p/VPC-4-in-x-10-ft-PVC-Sewer-Pipe-6004/202300536 $13.77 for 10'