The water spigot on the side of my house leaks. Is this the kind of thing I am going to need to replace the entire thing?

I had a similar problem and was unable to find replacement parts, so I replaced the whole spigot.

There are rebuild kits for frostcocks with anti-siphon valves. Find what you can regarding brand and part numbers on it and you'll surely find a kit for it.

There's a little flimsy poppet that gets pushed up and seals on the circle when there's water pressure. A couple years ago I fixed one at my parent's house where the poppet was simply out of position.

Frostproof hose bibs go deep into the wall. Replacing will likely involve cutting into the wall.

That looks like it's right above skirting like mine, so they might be able to crawl under the house and replace it

Frostcocks. That's a new word for me!

The official nomenclature would be a frost-free sillcock but that's not much better :)

I bought a kit and it didn't work. Then remembered my brother left a plastic organizer in my garage from the car wash he worked at. It had everything I needed. I got lucky.

You should. Its an anti siphon device that as described in other posts can be repaired/ replaced. But your best bet is to replace the entire spigot because of age and variation in parts ( they are not universal and every manufacturer loves to discontinue parts) if this was damaged because the hoses/ splitter was left on during freezing weather it probably damaged the entire unit. You should also install a isolation valve when you replace it for future issues. Also as others stated it is a frost free spigot and truly is not a big job with some common plumbing. Its usually accessible in the joist below the floor not so much "in the wall"

E: and take the damn hose off in the winter

Just make sure to get the angle correct, otherwise the "frost free" bit won't work so well.

I went under the house today to look at what would be involved in replacement. The insulation covers the plumbing. So I took my pictures and went to the hardware store. They had a replacement. Got home, and after a bit of struggling I got the old anti siphon device out. Turns out it was not broken, just the piece that lifts was off kilter and stuck. Put everything back together, and then I remembered there is also a leak the comes through the hand wheel. But it is far less than the leak that was through the anti siphon device. Maybe next week I will replace the rest of the spigot.

Right on. Let me know if u have questions. I'm usually on here judging others peoples repairs instead of fixing my own broken stuff.