So if I wanted to do a step-function graph for gas prices, how would that work? I'm a little confused. Could someone give me examples please? That would be so helpful (: Thanks!

if you knew that gas went up 2 cents every week, you might use something like

p = 3.299 + 2⌊x⌋

where x is the number of weeks
and p is the price, which started at 3.299

To see some examples, you can go to

wolframalpha.com

and enter

plot 3.299 + 2⌊x⌋

you can play around with various numbers and see what happens

you can also use int(x) for ⌊x⌋