Okay so you need to some cash, a very good knife or xacto blade, and a large retail chain.
What you want to do is go to a Store and Grab the WoW Battle Chest. That is the one with Both WoW and The Burning Crusade Expansion pack in one box. Pay for it, Get a receipt and the return policy for retail chain should be printed on the back of that. Now You can take home your software.
When you get home get your xacto knife and carefully use it to peal up the round stickers that seal the box flaps. Be careful not tear the printed part of the box or peal it up with the sticker.
Another Easier way to do this is use a heat gun or very hot hair dryer on the sticker to melt the glue a bit. But you may not have one of these. As most wow players are male.
Now you just need to pull out the content of the package and find the account codes. Either write these down or keep them out of the box.
Replace all your items the way they were packed. Reseal the box with the stickers. If you used a hair dryer so super glue, model glue, etc will help seal down the clear circular stickers that seal the box.
If you have a little bit of skill your box will look unopened. Take it back to the store and tell them "Hey I bought this game and didn't notice you need a DVD drive to install it. I got home and saw that it says it has dvd discs. I need to exchange it for a copy with cd-roms".
Now here is thing I haven't seen a store with CD-Rom battle chests. So look and then come back saying "You guys don't have a cd-rom version can I just get my money back?"
I have done this twice. Once at Wal-Mart and Once at K-Mart. Try target, EB Games, Gamestop or any major chain. Smaller stores tend to have stricter return policies and smarter employees.
If the store refuses to give your cash ask for store credits and get the TBC and WoW in the separate boxes. Either way you go you just got something for nothing. Well almost. Takes a bit of your time and some effort.