ADVICE please......?

what are some discreet ways to figure out if guys are single and interested. sadly i havn't seen to many guys i'm all that interested in, but i met on guy in my college cl, he's cool, he's very nice to everyone, he somtimes jokes with me and calls ME ist, and then i dish it back, it's almost flirtatious but i cant tell. the only way i can tell if a guy is interested is if he practically begging, and then i know he's not right anyway. this guy isn't watching my every move, but is nice when he see's me. how can i discreetly figure out if he's interested in me. i wouldn't want to ask him to get coffee after cl if he turned out to be taken and uninterested. advice?