I don't understand the Lol part by Lusi,
here in U. S. many indian saree stores, sell ready made falls (its basically just long strip of fabric of appropirate width ,lenght, and fabric), which then get hand stiched (by turpai tanka) on to the sari that you have bought separately...also ready made petti coats are sold.
may be in pak there is no need for ready made falls, as darzis can make them from suitable material and stich them on the sari...
but that doesn't mean that ppl don't buy ready made falls separately any where else
some times, saaris come with falls already stiched on them, but falls are definitely sold (and bought) separately as well here in the US as far as I know.