I won't get into maintenance issues with any of these airplanes. Although they are all different in many ways they use mostly the same materials and components the main difference that the Luscombe is metal (some have fabric wings) and the condition of any used aircraft you get is going to be completely dependent on what kind of treatment it received over the past 67 years. If you are in the market for one of these aircraft I'd suggest not nailing yourself down to a specific model, just try to find the best condition for the best price - the best deal and as said don't discount the Chiefs because you can usually get a good deal on them as nobody wants steering wheels.
There's also the Cessna 140's
That is sound advice...
Only flown a Champ, a Cub, an Aeronca L3, and a couple of 140s (including one with an O-200),and I've done a lot of research on the other old 2-seaters mentioned above. I still don't own anything, but I've done plenty of window-shopping and some tire-kicking. If I were looking to buy one of that group, with economy as a primary concern, I'd think first of a Champ. BUT.
They can all be flown and maintained pretty cheaply (including T-craft, Chief, and Luscombe), but not all examples of make/model/year are equal, especially after so many decades. The potential for (legal) modification is staggering (I've seen a C-120 with a C-85, flaps and an IFR panel, for example), which complicates the selection process, and the potential for serious abuse, neglect and bad repairs over so many years is also staggering, which dictates a very thorough pre-buy inspection, preferably with someone very knowledgeable. It's wise to be open-minded about which make/model to buy, but there are soooo many flavors to choose from, it will take some work.
The upside to the vintage 2-seater market, though, is that there are a number of type clubs and web forums, with some very helpful and knowledgeable members. You'll get leads on planes that are not advertised yet, you'll probably hear from someone who has the "inside dope" on some plane you're looking at, you'll hear all about what it takes and costs to do maintenance, where to get parts and services, and you might make a friend or two and get some stick time in some type new to you. I'd sooner start my search through such a group than cold from the classifieds.
Here's a couple, off the top of my head...
When I was contemplating buying a 140, these folks welcomed me and several were very helpful, and generous with their airplanes. Just about anything you need to know about those Cessnas will be found here.
http://www.cessna120-140.org/
Via the Luscombe Endowment, the "go to" guys in the US for anything to do with Luscombes. Doug Combs is a bottomless well of Luscombe knowledge.
http://groups.yahoo.com/group/luscombe-silvaire/