i wait for Futureshop or Bestbuy to put them on sale and i get a 100 pack of maxell or memorex dvd + r for $30/canadian + plust tax. (approx 36 cents per disc. thats pretty cheap) they go on sale to that price about 3 times per year.
in 2 years, i have only had about 30 coasters in over 3000 discs. (most of those coasters were my fault)
as the above posters have said, burning dvd files to cd is a complete waste of time.
you would be better off to just convert the file to a codec at a high bit rate and watch them from any computer. this way you won’t need discs at all.