Carla,
I Googled "Tire Top Off" and found one on Amazon sold under the Slime Brand. Is that the one you were looking at? The Amazon review on the unit you mentioned has a 3 star rating with with 76 customer reviews and produces 50 lbs of pressure. It sells new for $12.99 AMAZON 50
This one sold on Amazon under the AAA Auto Brand is less than $3 more but has 4 stars with 1360 customer reviews and goes up to 300 lbs of pressure. It sells for $15.77 AMAZON 300
Not that you will use 300 lbs of pressure, but it means it will inflate your tire much quicker and easier and put less strain on the tiny motor of the first unit.
edit: Just read the full descriptions of both and need to add: The size of the Slime Brand is smaller if that is an issue. That said, the Slime unit might work fine for your needs.