PSA Dagger (Glock Clone) - There's usually models available for these prices-- around $300 for base gun, a bit more for different sizes and features (optics cuts and threaded barrel, for example), as well as kits with extra mags and/or cases.
$369.99 with range bag and 10 mags
$409.99 Full size with optics cuts, threaded barrel, 10 mags, and range bag
https://palmettostatearmory.com/s-w-m-p-shield-2-0-9mm-no-safety-black-11808.html
$299.99 - S&W M&P Shield 2.0
https://www.sportsmansoutdoorsuperstore.com/products2.cfm/ID/281522
$399.99 Glock 17 Gen4 Police trade-in
https://www.familyfirearms.com/product/glock-px4350201-g43x-9mm-luger-3.41-101-black-black-ndlc-slide-black-polymer-grip
$412.96 Glock 43X
https://www.kygunco.com/product/cz-usa-95132-qp-only-usa-p-10-c-9mm-3-15rd-mags-blk-3-dot-ns
$419.99 CZ P10C
https://old.reddit.com/r/gundeals/comments/zb2adn/handgun_steyr_m9a2_mf_9mm_luger_4_171_40799/
$408 Steyr M9-A2
I don't know anything about this handgun, so I linked the discussion thread. Most of the comments seem positive.
Taurus - They've had a bad reputation (for good reason), but their recent models (G2x, G3x, GX4, and TX22) are supposed to be good, especially for the price. Do your own research.
$237.66 GX4 Micro Compact 9mm - Micro compacts in 9mm can be pretty hard to shoot, fyi.
https://www.shoot-straight.com/product/cz-75-b-omega-16rd-semi-auto-pistol-9mm/
$549.00 CZ 75B
https://www.familyfirearms.com/product/glock-pa195s203-g19-gen5-9mm-luger-4.02-151-black
$494.99 Glock 19 Gen 5
S&W M&P Sport II - Usually priced around $500 right now for base model. Will fairly frequently see sales with extra mags or other accessories for around this price. More expensive packages include iron sights or red dots that may or may not be a good value.
$499.99 Optics ready with 5 hex mags This one pops in and out of stock
PSA ARs - From what I've read these are usually fine for the cost. They may have QC issues (most manufacturers do right now) so you'll want to make sure everything is within spec or send it back for a replacement. Recently have been priced a bit under $500 for base models. Can sometimes save a bit by buying an upper + lower kit and putting them together (make sure you get one with BCG and charging handle, or buy those separately.
https://www.sportsmansoutdoorsuperstore.com/products2.cfm/ID/283060
$719.99 CMMG Banshee 12.5" Pistol
According to Reddit comments it's comparable to the IWI Z-15.
https://old.reddit.com/r/gundeals/comments/z85rhg/other_brownells_buy_100_gc_get_25_gc_free_right/
Brownells gift card bonus. May be worth it if they have a gun you want at an already-fair price. Read discussion for more details and opinions.