NO!
If you have the ability to generate business on your own - ROCK OUT!
Leads aren't required at all, they're only there if you need them.
If you need them, they vary in cost from $2-$50 and the only difference is how old the request is. New leads are more expensive, but they're exclusive.
Most agents leverage the lead system because once you get good at this, you can write your own paycheck.
There's no limit to available leads and once you learn how to convert them consistently to business - you can literally earn as much money as you want.