This might be better asked on Discord. As Redtrainer conveyed, there isn't a pre-configured method to achieve what you're saying - but you can pay less if you can't afford more, and still get something(such as the $2 amount mentioned).
If you're wanting to pay in installments for the highest tier, I imagine you might have better luck asking on Discord. I hope you're able to find a good solution. I'm happy to help if you have any general game questions.