The .25 is not a very powerful round. You can get some of those real nasty bullets if you look around. Super fragmenters, or super mushroomers.
That said the colt version is the nicest of the .25 autos. That one was bringing that money a couple years ago when I saw one sell at $250. There is a stainless one from colt too.
If you just want a cheap auto .25, the Italian ones from the 50s 60s are not too bad. You can tell they are better quality than the real junky ones when you look close. One of those should go$75 to $110.
FYI, I did a little unofficial testing with .25 ammo coming out of a Taurus PT-25, and my target was a few water bottles at 10yds. More specifically, I took 4 old Aquafina bottles, arranged them in a square, and put a single soaked paper towel roll behind it.
I fired 6 rds, and recovered all 6 just under the near side of the paper towel roll or lying in the grass beside it. I didn't change the bottles, or add more water after each shot.
.25 has far from decent penetration. Oh, it might kill someone alright, but if you don't get 'em in the head, it may take 20mins for them to croak.