Hiawatha (the native American from the poem) was a name used by Savage Arms for .22 rifles they made. The S-L-LR marking (L, not 1) indicates it will shoot .22 Shorts, Longs, or Long Rifle cartridges. Values will depend on exact model and condition, but these are not typically pricy guns- $100-$150 range.
you will have to go to gun shows and gun shops.
Blue Book of Gun Values
Sentinel DELUXE 22cal R-107
Blue Book of Gun Values
Blue Book of Gun Values has some information.
Try gun stores or gun shops
Try e-gunparts.com, gun shows, want ads, gun shops.
Berretta storm
Old gun catalogs
Both can be equally accurate
Check the web under "Air gun repair"
Best left to a gunsmith