Amazon has some for $22, but they're not prime. ArtToFrames 14x21 inch Satin Black Picture Frame, 2WOMFRBW26079-14x21 https://www.amazon.com/dp/B005MRTYT4/ref=cm_sw_r_cp_api_glt_i_SCFV95NFFP7JNXH683GP

I bought these from Walmart when I did my puzzle but they have gone up in price. 21x14 Frame Black Picture Frame - Complete Modern Photo Frame Includes UV Acrylic Shatter Guard Front, Acid Free https://www.walmart.com/ip/753167150