Best buy or Walmart (that is where i noramlly by my movies) has them on sale.
http://www.walmart.com/search/search...b_value=19_All
Transporter 1: $16.86
Transporter 2: $17.32
Transporter 3: $25.86
Total: $60.04
It is not uncommon to see the first two for around $15-17. Then it just depends on how cheap you can find the 3rd one for.