I'm not trying to put you down or your ambitions, but I have a few questions. The fact you're asking us about breeding cheap morphs as soon as possible is a little concerning. Or at least in my opinion.
Do you have any snakes already? Do you have Ball Python experience?
What kind of husbandry and set up are you practicing? Quarantine?
Do you have a plan for the eggs once they're laid?
For $300 you're not going to have much of a selection.
You can get an adult female normal $100-150. You can get a male pastel hatchling/well started for $75-125. Males take less time to mature, so if you get a hatchling, he could probably start breeding in a few months.
This renders you 50% normal, 50% pastel babies.
Nobody wants 50% het normal babies. Especially males. It's not worth breeding 50% and gambling time and money away when there are 100% hets on the market for pretty cheap already.
What are you going to do with the hatchlings if you can't sell them? You have to be prepared to house and keep them if you can't re-home them.
But regardless of what you get, it sounds like you're not ready to breed. Breeding snakes is not an instant thing, it takes patience. Lots and lots of patience.
Even if you get a pair for your budget, it doesn't mean either the male or female will breed.