Had a flat tire a few days ago. Now I'm [View all]

Debating my next move.
Picked up a screw and it went completely flat. Was going to take it off and take it in. Getting old and started to struggle with the lug nuts, so I gave that up and just plugged it. Seems ok now, but I’m not going to trust it.
The screw was right on the edge of the tread and almost on the sidewall. Figure the tire place won’t patch it and try to sell me a new tire.
Tires are at least 80% full tread. Thinking I might look for a used one on Graigslist or try a junk yard.
It’s a 2000 van with 15 inch tires, so hard to find these days, even new.

Any educated guesses on the best path to try?
Thanks for reading this.