the lake house market in Texas heavily depends on what lake you are on, what city and if you are on a canal or the main body of the lake. that house on lake austin, marble falls, travis, Dunlap, Placid, or Mcqueeney would run anywhere from 900k- 1.5 million depending on what part of the lake, flood zones etc...
on a very small lake that i don't like very much in Mc Queeney texas they are currently selling 1/2 acre lots, 100 ft water front, great spot on the lake for about 800k. My boss just sold his lake house on lake LBJ for 1.1 million, it was 2600 sq feet on a fairly nice lot. Lot of variation.