Hey everyone. I am wanting to learn the type of Latin that is used at Traditional Latin Masses. What would be the best and cheapest way to learn this type of Latin?
Ecclesiastical Latin is 99.99% the same as classical Latin, I did classical Latin and can read ecclesiastical Latin just fine.
Not only that, Latin isn’t something you learn in two weeks. I am doing it for five years now and still find things difficult.
If you are looking for a good church latin textbook, I would recommend Henle. Also, there is a group here that is looking to learn latin, so you may want to join that club. As the previous poster said, don’t expect to learn this language quickly, 4+ years of study and I still struggle at times.
Pick up the book, Primer of Ecclesiastical Latin, and start reading. Ecclesiastical - especially Vulgatine - Latin is no more Ciceronian Latin than is Spanish (excuse the exaggeration in service of a point). I learned Latin starting with classical and then picking up ecclesiastical, which took me far less than a year (although I had studied classical Latin before). I’m not sure whether one would have such an easy time starting with mediaeval and working one’s way back to classical - I don’t believe so. On the other (same?) hand, I picked up English with no antecedents nor cognate languages to my current level of ability in 12 or 18 months, and read the New Testament in the original Greek. Oddly enough, I have never managed to achieve such a level of proficiency in Hebrew nor in Aramaic despite study, although my native tongues are the Arabic (which is very similar to both Hebrew and Aramaic: similar enough that one can often wring out the contours of Hebrew meaning from nothing more than Arabic cognates), and to a much lesser extent the Coptic (as a liturgical language: spoken Coptic is relatively rare, akin to spoken Old Church Slavic: similar to Greek, in alphabet if not in grammar).
If you have never studied Latin and can not read or understand a modern Romance language, expect to spend at least six months studying intensely to attain even a most rudimentary proficiency, if you study as I do. Extend that to two years or more if one studies at the same rate one does in university.
Do you want to learn just to speak it (i.e., pronounce it/read it off the page), or to write it?
If you want to be able to write it, you need to learn classical Latin first. I will try to find my old Latin textbook from high school earlier – it was VERY good – to recommend to you.
If you just want to be able to pronounce it, it’s not too hard, just some minor differences. Use this EWTN guide to help: ewtn.com/expert/answers/ecclesiastical_latin.htm
Just a note, for those who might otherwise experience common frustration in learning another language. The best, proven way for anyone to learn a new language is through immersion, the same way we learned naturally as children.
However, you can’t travel to “Latinland” these days, where Latin is the everyday language.
The TLM and daily prayer offer probably the best opportunities for immersion in the Latin language in a classic sense.
We in the Byzantine-Slav tradition have a similar challenge with our “Latin”, which is Old Church Slavonic. Remnants of it can be found across the modern Slavic languages, but nothing is really close to it. It is through the Divine Liturgy and prayer that I have only begun, after many years, to start picking up grammatical patterns and vocabulary. I’m still handicapped, however, as I have never been able to get used to the Cyrillic alphabet, nor the characters that are used in “classic” Church Slavonic writings and printings.
At least there are many more resources for Latin, and the alphabet is readily recognizable to Westerners!
Res secundae! (itself a Roman idiom, which of course represents a further complication in learning language academically vs. immersion)
The closest you might get to an immersion course might be the *[post=2896305]Lingua Latina[/post] *materials, or the *[post=2538507]Cursus Linguae Latinae Vivae[/post] *(they are both inductive, if not immersive).
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And buy a lot of 3" x 5" index cards, which you can review daily. 
A person who learned Latin via Primer of Ecclesiastical Latin would not have difficulty making a later transition to classical. I have the impression it was deliberately designed to allow this.
I’m not sure it is the best book for a total beginner. I’ve come across people who found it difficult. (I didn’t use it until I was intermediate level, at which point it was great.) It would probably work for a motivated and determined beginner.
The easiest materials I’ve come across are those put out by Memoria Press. They can even be used by children. memoriapress.com/descriptions/index_latin.htm
There actually is an immersion course, but it does not meet the OP’s requirement of being inexpensive. http://www.hieronymus.us.com/ (scroll down for info in English)
CENACULUM FAMILIÆ SANCTI HIERONYMI GENERALE
W
IN BEAUTIFUL FLORIDA
TO BE HELD AT THE SAN PEDRO CENTER
IN THE CITY OF ORLANDO
Six days, from the 22nd through the 27th of July,
in this year of Our Lord 2012
The date and location change every year.
I’m starting to have second thoughts about taking Latin in school this fall. I remember trying to learn French, which was not easy and I retained none of it. At least I use Latin more than I use French, though I use the Ecclesiastical pronunciations. I hate how classical Latin sounds.
Learn classical Latin. It is much easier to move from classical to ecclesiastical than the reverse, and the classical Latin is better stylistically and linguistically than the Medieval Latin without a doubt; the Renaissance and NeoLatin restored the glory of the language.
I would recommend Wheelock’s Latin. Do not deprive yourself of the knowledge of classical Latin.