I used to get my used religious books on Ebay, including my hymn book collection, and bought my copy of St Gregory there, so you probably could find one there at a low price. also Amazon used books.
The Ignatius hymn book is great, but when I tried to get one, they wouldn’t sell to me: apparently a lot of folks are only buying one book and giving out the words to the congregation instead of buying the more expensive “congregation” version. so I merely copied the list of their hymns and found the hymns elsewhere.
I sight read music but play by ear also, so having only the melody is not a problem for me.
Modern hymns that are lousy from a musical standpoint ARE a problem. And so is Gregorian chant, which makes it hard to figure if you should use a major or a minor chord for accompaniment.
Proulx's accompaniments in the ECUSA hymnal are a good pattern also and very adaptable.