In autoloaders I prefer the ruger mk series by a small margin over the buckmark. A close third is the sw22 with target grips. By far the best pistol on the cheap I have ever had though is a phoenix hp22a. My first was when I was 14 or 15...cut a deal with my parents that if I brought a D in chemistry up to at least a B I got a gun...I got it and around 12000 rounds later rebuilt it, around 3000 rounds later bought another one. I have had 4 now. Sure they wear out...but they are very accurate, very reliable, and are still like $125.
In SA revolvers the ruger single six or Bearcat are hard to beat. I'm on single six number 3, barrel keeps growing longer with each new gun. Accuracy does increase, but marginally. On the cheap though a rough rider with the shorter barrel...4 5/8???...is well balanced, very quick, and acceptably accurate. I plan to buy a second one of those with a birdshead grip just for fun. A bonus on those is that they have a thumb operated hammer block safety. Finish is poor, but on a $149 gun once you beat the snot out of it you can rattle can it back to black and go for round 2 and not feel bad about it. There are other high and low end guns here as well, but I won't even consider any other except a colt frontier.
In DA revolvers it's pretty hard to go wrong if you buy from a company you have heard of. Charter, Taurus, Ruger, and Smith & Wesson all make quality guns. Of the bunch the best for the buck is a USED taurus. In new guns the price is too close to make much fuss over so buy the sp101 or the smith j frame that fits the best. In used guns they hold about 80% of their value though, and a 99% taurus will hold about 65% of its value. So you start with a 350 dollar gun, and now your around 225 or 250 when the others are still 350+. Charter guns are similar in price to taurus, but charter has made some absolute crap so it's kind of a crap shoot on those (pun intended). Taurus has made junk too, but they stand behind their guns pretty well. It may be slow but they will take care of the customer whether they bought a new gun or a secondhand beater.