Is it my ignition or my key?

I'm having an issue with my Gen 1 Prius that maybe someone can help me with. My mechanic says they can run some tests to figure it out but just the tests might take a couple days. Hopefully someone has some experience with this and can save me some time and money.

About a year ago, my key stopped working in the trunk lock. I assumed it was the trunk lock messing up and did nothing to fix it since I could still use the trunk release from inside the car, and because I'm too broke to fix something unless it's absolutely necessary.

About 2 months ago, either my key or my ignition started messing up. It doesn't do it everytime but it's more and more often the longer I take to have it fixed. I'll go to put the key into the ignition and it'll stop with about a quarter inch left to go in to be able to turn the ignition. I have to take the key out and try it again. I try turning the key around, jiggling the steering wheel, hitting the brake, pretty much anything you can think of. It take me up to 10 minutes sometimes just to get the key in the ignition to the point where it will turn. It started out doing this maybe once a week, now its at least half the time, so pretty much an every day thing, sometimes 2 or 3 times a day. I have to leave the key in the ignition whenever possible just so that I'm not late getting to work, or wherever I'm going, because I had to fight with the car just to get the key in.

My mechanic says it's probably either the tumblers in the ignition wearing out or the key itself wearing out. I don't have a spare key to test if it's the key or not. If anyone has any experience with this I'd appreciate what advice you can give.

 

The key will turn once it's in the ignition, it just doesn't want to go all the way into the ignition to be able to turn. It stops with about a quarter inch left before the key is all the way in the ignition. I did try putting some PB Blast (I think that's what it was called anyway) into the ignition, my mechanic said it's a great grease for ignitions that aren't working quite right, that maybe it just needed to be lubed.

The shifter is in park when I try.