Apple charge £160 for an upgrade to a SSD.
You can pick up a comparable, if not slightly better SSD from a third party for a lot less. An enclosure costs all of £10, so you are most definitely not loosing anything, in fact you are gaining a 500GB external hard drive as well as a faster SSD inside your MacBook.
The general rule of thumb always has been, and probably will remain never buy user upgradable parts from Apple unless you absolutely have to!
Edit* What's more in giving Apple your money to upgrade to an SSD you are in affect loosing the 500GB hard drive, it just doesn't make sense to do this.
You can pick up a comparable, if not slightly better SSD from a third party for a lot less. An enclosure costs all of £10, so you are most definitely not loosing anything, in fact you are gaining a 500GB external hard drive as well as a faster SSD inside your MacBook.
The general rule of thumb always has been, and probably will remain never buy user upgradable parts from Apple unless you absolutely have to!
Edit* What's more in giving Apple your money to upgrade to an SSD you are in affect loosing the 500GB hard drive, it just doesn't make sense to do this.