The digital scale is just really to keep a close eye on weight gains. You want a nice steady weight gain especially as babies and one of the first things you'll be asked if you ask a question about feeding frequency or size of prey is "how big is your snake". Since length doesn't mean all that much, weight is a vital thing to know. No need to buy a hugely expensive digital scale, department stores or office supply stores often have nice scales (either kitchen or postal) for $30 or less. If you run a search here on digital scales you'll likely come up with loads of threads.

The other way of determining proper prey size for ball pythons is to compare the largest girth of the prey (on rodents that's the butt/hip area to the largest empty girth of your snake). A lot of us go with equal to or slightly less than girth so that when the snake eats it does not have a distended feeding bump. Others feed other ways, using other standards. As far as using weights - I generally go every 5 days until they hit about 150 to 200 grams, then every 7 after that weight is achieved.

My kids are much the same LOL. They think it's perfectly normal to have snakes all over the place. Whenever a new friend comes to play with my youngest whose 6, and they get all googley eyed over the snakes, young Michael tends to sigh, roll his eyes, shrug and mumble..."they are JUST snakes...geeze!".