Smart Key wacky issues (please help :)

Hi Prius Pals. Greetings from Connecticut!

So one night last week my 2005 Prius's alarm just went off in the middle of the evening. We ran and grabbed our (only) remote, and were able to shut it off. 5 minutes later, it did it again.

The next day we noticed that our key wouldn't remotely unlock or lock the doors anymore. No beeps when hitting the buttons, no lock movement. However, you could still open the doors via the sensor in the door handle and then start the car. Must be the battery, I thought. But after replacing the battery twice, no change.

So Sunday I'm at the church I pastor, doi a bug BBQ Party after worship to celebrate the end of our VBS week (thank goodness it is over...), and the alarm goes off again. Everyone gets to se me run to the Prius, and try to stop the alarm with the remote. It took many frantic presses of the remote to get it to finally shut off, and then it started up again a few seconds later. I had to sit in the car and keep trying to start it quickly before the alarm went off again. Finally I got it going and parked the car waaaaaaayy down the street so it would be too far for the remote to do anything (assuming the remote is the problem!).

This happened again on Monday, and now we are away on vacation until Tuesday. So I'll have to tackle the problem then. As these things happen, we are in a rough spot about what course of action to take - my wife just recently lost her job, plus we just had to move, so finances are crazy tight.

Anyone run into anything like this? I have many questions:
- Is it my remote failing or is it the system on the car's side going out?

- I've been doing lots of the reading on here about what I may be looking at if it's the remote that needs to be replaced. Hopefully they can still use my (failing) remote as a basis for programming new ones. I know I'll need silver-logo replacement fobs (that's what ours is), and that it seems like I should only buy new (I programmed) ones if I want all the smart features to work, and have them programmed at the dealership, correct?

If we decide that all the smart features aren't necessary, from what I gather we can save some money and get used ones, and have the car programmed for them, though they will just start the car when inserted into the dash, correct? If that the way we go, and we find black logo fobs even cheaper, could we use those? They aren't designed for the smart features, but if that's what we expect, is there another reason why they wouldn't work with our Prius?

Any help anyone can offer would be much appreciated.

 

The one in the trunk? Just replaced it, maybe 6 months ago.

 

We hadn't changed the battery for a while, at least 4+ months.

 

Ok, I'll have to check that when we get back from vacation, I guess. Thanks, friends.