Why is my iPhone 3g obsolete?

I have had this phone for quite some time, and I understand they want you to get the iphone 4 or 5 but I don't really have the money or want to spend it on a new one when my old one works as far as calls and texting etc… But no apps work, one by one they are starting to fail, won't load, etc. I had instagram since I got my phone and it stopped working and I'm very annoyed with Apple!

Its a sign from the Apple gods that its time for an upgrade.

You should try turning it off and on or factory reset (ONLY IF YOUR APPS ARE BACKED UP!). Alternatively, you can just go into the store where you bought the phone and they will be happy to help. I have had problems with my phone before and i went into the phone store and they fixed it for no charge at all.

This sounds similar to your situation: http://iphoneaday.wordpress.com/2008/08/17/iphone-apps-not-working/