What's A Roll Of 1940's And 1950's Canadian Nickels Worth?

Without knowing dates and conditions? 2x Face.

This depends uncirculated or circulated for the 1950 roll I would assume circulated besides 1950-d $5 1954 S S/D , 1955 D D/S most are at face value.

I bought 1950's rolls like this $5 but ended up getting same coins I found latter from circulation most the same coins in bank rolls at face and I only get 3 rolls a week for 2 months. As for the 1940's if they War Nickels I think they go for about $1.80 for ones between 1942 - 1945-2 they contains 35% silver. but 1940-1942 is face and 1946-1949 face. But think most collector would of said War Nickels or had them separate most likely as the value greatly different?

I would buy both for a total of no more then $8-12. which is a risk hoping for a War Nickel or two make up for the cost. If the whole roll is War Nickels melt is $44.95 but odds are against that.

I would pay no more than around 3 x face for canadian nickels in that date range no more than 1.5 X face for American nickels in that date range

It is hard reselling these for more than face, but I encourage you to pay a small premium above face for the fun of searching them.