yes.
On the triggers for the shipping rule, use "Taxable total For the Cart"
If the taxable total for the cart is '>' '0'
AND
If the taxable total for the cart is '<=' '4.99'
Flat rate shipping of '1.25'
then create the second rule as:
If the taxable total for the cart is '>' '4.99'
AND
If the taxable total for the cart is '<=' '14.99'
Flat rate shipping of '5'
you will need to create a shipping rule for each price range.