Blog posts discussing Good ‘Til Cancelled, eBay’s standard fixed price listing duration that creates a static URL for each product page.

eBay SEO 101
eBay SEO and Good ‘Til Cancelled (GTC)
The eBay SEO methodology of utilizing the benefits of Good ‘Til Cancelled (GTC), even if it means spending some extra insertion fees, far outweighs the treacherous alternative. […]