My Mom has been in JL for almost 10 years now, she's not nearly involved in it as she once was due to her job that she didn't have at the time.
I kinda tell my fellow greeks that JL is like a Sorority for older women, without the partying. They have meetings, they do community service, they have occasional social events, including "formal". That's where my own involvement came, at the JL Community Ball. The first Saturday in December each year is the Community Ball, and they have a Cotillion for all the HS seniors who are either children or grandchildren of members. Very formal - Girls have custom made dresses ($534.52 with tax

) that are all identical, plus shoes, diamond tiaras, matching earings, and gloves. The guys are in tails always, and sometimes they get top hats and canes (unfortunetly my year we didn't get those

) It was a lot of fun actually learning to waltz, and meeting people from other schools, plus my "class" was full of hot girls (which isn't always the case) so that was cool.
There isn't that much cost tied up in dues, most of the money is just for administrative costs. A lot of the money raised is through things like the Community Ball, they have a cookbook they compiled (treasures of the Great Midwest, it's wonderful if you can find it), They also have a bunch of other projects that happen throughout the year.
I would say that in KC there wasn't a "snobby" aspect to it that much. No more than say sorority membership here in the north. I guess you could say the Cotillion is a showing off of daughters, and is definetly a bit pricey for the girls (guys tux rental was actually much cheaper than normal rentals) in sort of a snobbish type of way.