A stovetop ventilator can be purchased for as little as $200 with exhaust fan and vent for installing an inexpensive  flexible 6 or 8 inch aluminum ducting.  Another option is installing a window fan but the stovetop hood does a better job of venting the smoke outside.

Although the TostaCaffe brand of coffee bean roaster have a dedicated exhaust system, the addition of a window fan or stovetop hood helps keep the roasting area completely clear of smoke resulting from cool down or the roast process.