I got this, it’s made in china but seems pretty decent quality. I got it for $100 but at this cost it still might be cheaper than getting a proper in-line fan and carbon filter combo.
My setup is in a closet and I vent it out of the closet so it’s always sucking air in and filtering the air that leaves.
LAYOND 4 Inch Carbon Filter Grow Tent Ventilation Kit, 200CFM Super Quiet Inline Fan, Bigger Capacity Charcoal Filter, Variable Speed Controller, 10ft Ducting, Thermometer and 5ft Power Cord Adaptor https://www.amazon.com/dp/B098D7F3K4/ref=cm_sw_r_cp_api_glt_fabc_29AM7R848F8NM9XQDJ3W?_encoding=UTF8&psc=1
I got a heavy duty carbon filter for grow tents: LAYOND 4 Inch Carbon Filter Grow... https://www.amazon.com/dp/B098D7F3K4?ref=ppx_pop_mob_ap_share
Something like this might be overkill but no complaints yet.