Forever Stamps – 100 stamps for $44.19 A/C @ Boxed.com – Possibly new customers only

Boxed.com has USPS Forever Stamps 100 Count for $51.99 with free shipping.
They’re $44.19 with 15% coupon code "LOVEBULK", which is a one-time use coupon. I’m a new customer, but description doesn’t say "LOVEBULK" code is for new customers only.
Codes:
JAN15 – 15% off any purchase (new customers only)
LOVEBULK – 15% off any purchase & free shipping