I'd save a little more and get to the $400 mark for a semi-auto. New SP2022 in 9mm from CDNN, used G19. Get your hands on a bunch and shoot as much as you can to see what fits you best!
You can get J-frames used in the 3-350 range too if you can go revolver.
If you are looking for a defensive handgun (and I assume you are if you're going to be carrying it IWB), then I'd make price your very LAST qualifier. Things that should come first are reliability and shootability (very broad category).
Try this: Borrow a buddy's handgun and take this class-- https://www.indianagunowners.com/fo...co_-_intro_to_defensive_pistol_in_2010_a.html . In the class, take note of what guns other folks are using. Take note of the ones that run, and the ones that have problems. Talk to the instructors to see what they'd recommend. Ask other students why they bought what they brought.
Soon you'll be able to whittle down the features that are important to you.
If you decide to take my advice, you're more than welcome to borrow my Glock 19. I'll even get you set up with the spare mags, a holster, and magazine pouch. Your $300 should EASILY cover the tuition and ammo cost.