If $300 is your budget, try and find a used Gen 2 Glock 23. Or even a Taurus would work just as fine. I own two Taurus' and though they get poked at, I have not had an issue except for the revolver and my PT745 shoots great with zero issues
You need to find out
1. What is the primary purpose of the firearm
a. Concealed carry/defensive use
b. Range/target use
c. Additional Gun for whatever
d. combo carry/target
2. How much shooting will you do will be a tool in the size and caliber you choose
3. Is it...