Lymon is 29, straightforward kind of man. He is also the business partner/friend of Boy Willie. Lymon is from the South. Lymon is running from the sheriffs down south for a "misunderstanding". He is a supporting character to Boy Willie. He is treated like he is young and dumb.
"I got it like you got yours. I know how to take care of money". (pg. 5-6). Lymon says this when Berniece questions him on how he got a truck. It's a response to a Boy Willie. The significance of this scene means without Lymon's truck, Boy Willie and Lymon wouldn't be up there selling watermelons. So he should be treated as though he has done good.