Is it still possible to use an original iPhone as your daily driver?

Half nostalgia, half 'broken phone on contract, need something to tide me over for 4 months'. Either way, it's led me to want to (re-)purchase an iPhone 2G.

So, questions....

* Is it still possible to download apps for it, outside of jailbreaking? Many apps (such as Facebook) state that they require at least iOS 4 - would I be able to download an older version of the app?

* Are any of you (or acquainances) still rocking a first-gen iPhone? If so, why?

* What do you think is a 'fair price' to pay for such an antiquated luxury?

Regards, HP.