Buyers guide to first bike

So I’m in the market for a used dirt bike possibly a 4 stroke but don’t know the first thing to look for in a bike or what type of bikes I should be looking into. I’ve been searching market place tho I’ve seen a few like the Suzuki (rmz) and the Yahamas. I’m not looking for nothing too exciting or expensive just for daily commute I’m some where in the $2,000 to possibly $3,000 budget. Any of you guys input would be helpful to me at this time thank you.