Need more info. Size of fireplace? Status of the chimney?
And for 500-600 bones you won’t get anything more than a set of gas logs (vented or vent-free), unless it’s from Home Depot or something. And if that’s the case I wish you the best of luck with it.
And vent-free is great, but only if you use it as it’s meant to be used… Hour here. Hour there. And it has to be a decent brand. You will have issues otherwise.
Both have their ups and downs.
EDIT_
A decent vented insert (natural vent) will run you about $2200 - $2500 installed. They start around $1700 - $2000 in materials.
Vent free inserts start around $1500 installed. They are about $1200 - $1300 in materials.
Gas logs are around $500 - 900 for a decent set with heat (either style). You can always go with a ‘dual listed’ set and run it vented OR vent-free and switch it up. You can set your damper at any setting you want.