First, ensure that the album you're looking for is indeed "August Underground's Penance". There might be confusion with the name or the artist. August Underground is known to be associated with the music project of Piotr Kowalczyk, a Polish musician.
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eBay, Amazon Marketplace, or horror collector groups on Facebook sometimes list original Penance DVDs. Prices range from $50 to $200. Be wary of bootlegs — authentic copies have the Toe Tag Pictures logo and a unique catalog number (TTP-003). august underground penance download