being cheap myself, the best i've found for under $100.00 that is repeatable is that 4-16 centerpoint. but as the OP eluded to, may look a bit retarded on a lever.

i've replaced enough BSA's to know to stay away from them. even having to replace the replacement scope. enough said.

a simmons and bushnell would probably be the next low dollar scopes not retarded looking scope on a lever, being tied with a tasco and a barska.

you can find either of the three easily enough from low power fixed to variable 3-9x or higher for under $100.00, and even under $50.00. the market is flooded with them.

IMO with a lever, almost any scope looks retarded, a nice set of fiber optic opens or adjustable opens / aperature sights seem appropriate.

yet for the sake of the squirrels, a scope should help, but he'll still have to know how to hold over / under at further / closer distances.