The Complete Proper of the Mass for Sundays and All Feasts of the Liturgical Year by Green & Koch for McLaughlin & Reilly Publishing (1946) (Buy it now $49.95 or best offer)

1956 Graduale Romanum, Desclee, Current bid $10.49

Not chant per se, but something that might be of interest to the forum readers:

2003 Book of Divine Worship, Newman House Press, Buy it now $125.00.

Chant books themselves:

1945, Gregorian Chant Textbook for Seminaries, Novitiates, & Secondary Schools by Andrew Klarmann (Gregorian Institute of America). Buy it now $14.95.

1990, Gregorian Missal, Solesmes. Buy it now $11.99.

Liber Hebdomadae Sanctae Cantus Gregoriani. Buy it now $16.99.

1930, The Plain Chant of the Ordinary of the Mass Adapted from the Sarum Gradual to the English Text, Plainsong and Medieval Music Society/Nashdom Abbey/Burnham Books. Buy it now $30.00.

1951, Details about Gregorian Chant Analyzed and Studied by Marie Pierik (Grail/St. Meinrad). Starting bid $9.99.

1957, Cours Elementaire et Pratique de Plain-Chant Gregorien by P. Balduinus Van Poppel (Westmalle). Starting bid $9.95.

1958, Gregorian Chant by Willi Apel (Indiana University Press). Starting bid $9.99 or buy it now $30.00.

Liber Brevior Buy it now $34.99.

1967, Graduale Simplex, Vatican Edition, Buy it now $68.00.

St. Gregory Hymnal. Starting bid $29.99.

1961, Graduale Romanum Desclee. Starting bid $49.99 or buy it now $79.99.

1959, Singing in God's Ear by Dom David Nicholson, OSB, Desclee. Starting bid $6.99.

1783, 1783 Breviary & Missal of Limoges France, Buy it now $299.00.

1987, The Anglican Chant Psalter Ed. Alec Wyton (Church Hymnal Corp.). Starting bid $19.99.

1980 Carmelite Proper Offices for the Secular Order, supplement for the divine office. Starting bid $11.99.

1792 Martyrologium Romanum: Starting bid: US $125.00; But it now: US $199.00.

2005 Carmelite Missal, novus ordo: But it now: US $29.99 or make an offer.

1582 Processionale Secundum Usum Romanae Ecclesiae, presertim Fratrum Minorum: Current bid: US $108.50

1953 Chants of the Church, edited by Solesmes and published by the Gregorian Institute of America: Starting Bid: US $6.99

1956 Liber Usualis, Desclee, rubrics in English: Buy it now: US $50.00 or make an offer. (This appears to be in slightly better condition than the similar one above, but more expensive.)

Papal Legislation on Sacred Music: 95 AD to 1977 by Robert Haburn: Buy it now US $75.00 or make an offer (there are chepaer copies on Amazon.com, but perhaps you can get it cheaper by making an offer.)

1978 Liber Cantualis inscribed by Theodore Marier to "Father Killian": Starting bid US $10.

1978 Liber Cantualis: Starting bid: US $4.00

1953 Kyriale Seu Ordinarium Missae, Ratisbonae: But it now: US $6.95 or make an offer (relisted with more favorable terms)

1923 The Office of Holy Week by Leo P Manzetti, P.J. Kennedy: Current bid: US $8.50

1952: Liber Usualis Missae Et Officii Pro Dominicis Et Festis
http://www.ebay.com/itm/Liber-Usualis-Missae-Et-Officii-Pro-Dominicis-Et-Festis-Book-William-C-Meagher-/291208890471?pt=LH_DefaultDomain_0&hash=item43cd670867
Buy it now U.S.$74.95.

Appears to be modern notation???

1874 Paroissien Romain, Marseille: Starting bid: US $19.99

2007 Mundelein Psalter, Hillenbrand Books: Buy it Now: US $49.99 ($4.00 shipping)

2007 Mundelein Psalter, Hillenbrand Books: Buy it Now: US $45.74 (Free Shipping)