La Tania is nice - and you can catch the bus easily to get around to Courcheval if you don't want to ski there.
For cheap look at some of the coach companies, like
Went to La Tania witht the former some years ago, and to Valmeinier with snowcoach a few years ago.
Valmeiner was a hotel but the atmosphere is like a big chalet - you all eat at the same time, etc. We got lucky at the Chef was a Michelin chef wanting a season at a ski resort!
The hotel is near the main lift and you can link round to the other resorts easily - apparently that area was scheduled to be the original 3 Vallies but it didn't happen for some reason.
The hotel has rental facilities and staff that guide, but don't coach, so it is easy to find a group of people to ski with.
I also heard good reports about their other hotels from snowcoach regulars at the hotel.
They are coach trips to take 15 hours or so, but the seats are big and have a big recline so if you take a book or media player and a sleeping bag it is cushtie if you are the type that can drop off to sleep easily. No fussing around keeping track on the kids either.
skiweekends use the chunnel and have a little quicker journey time, snowcoach do a bit of a circular route picking people up and then you take the ferry, so more hassle.
The coach trips get you 8 days skiing whereas someone flying might get only 6.
IMHO brides les baines is a little too far down the slope for comfort, but if skiweekends go to La Tania again I would consider it - I would rather sit reading a book or watching a movie than mess around with all that dead transfer time when flying.
http://www.skimeribel.co.uk have coaches with seats that turn into bunk beds, but they look a litle more expensive than the others. Meribel is a good looking resort though, although Chourcheval is nicer for beginners with those big motorway greens back to 2000.