I'm tired of the super high fees I'm paying to my current cell phone provider and I'd like to move to another carrier. Can I keep the same phone number and can I use my existing phone?
You should be able to keep your same phone number when moving from one carrier to another. The concept of porting your cell phone number should be transparent and it should happen when you set up service on the new carrier. Just tell them you want to do that.
In terms of keeping your same phone however the issues aren't connected you can keep your number but get a new phone. The phone number and the phone aren't related really but in terms of keeping your same phone that is questionable. Some phones will work on multiple different sets of frequencies that different carriers use. Other phones are limited to a particular set of frequencies.
You'll need to ask when you're moving to the new carrier about your old phone, but one thing's for sure if you purchased your phone through a carrier you'll need to make sure that phone is unlocked from that carrier before you move it to a new one. If your phone is paid for your carrier should be able to unlock it for you. If you're still making payments they're unlikely to do that.
So in summary you can keep your old phone number. You may be able to keep your same phone.