Buying on/off spread of 3 and 7 for 10c

I've heard of a book not charging a premium for key numbers on a football spread. What is the expected avg. return with a 10$ bet at -130 to move spread 2.5 to 3.5? Same question for the 7 and 10. Is this a potential money maker? Is there a difference of roi nfl vs college?


Here are the costs

Points bought

.5 -120
1 -130
1.5 -150

Would is be a positive roi to buy 1.5pts to move the spread thru the 3 or 7?

I've come across the calculator here: /games/sports-betting/nfl-spread-calculator/ but I don't believe that factors in juice. Would juice just be 10c?

Is it beneficial to buy .5-1.5 pts for and key numbers on the over under?