Nice idea. Thank you mate!no idea about the price...BUT - have an idea how you can promote it.
Shouldn't cos too much either... create a Facebook advert targetting ONLY people who's birthdays are on the 11 September (assuming they allow you to target down to exact birthdate)
Have a nice catch line and Banner showing 11September.com ... then direct them to ur sales page..
Tell them on the sales page they they can even create a personilzed email address. [email protected]
Just a thought....