If you plan to buy on behalf of your clients from your own account. Eg. if you are an agency who buys on behalf of their clients then you should consider being a partner. Partners are eligible for upfront discounts depending on the number of websites they secure.
If you plan to promote Astra for others to buy and then earn a commission then you should become an Affiliate. Eg. If you have a blog where you plan to promote Astra and earn commissions whenever any reader of yours buys Astra, or if you are an agency and your clients prefer to purchase Astra themselves, you can use your unique affiliate link to achieve that and earn commissions. Affiliates get a 25% recurring commission on the purchase amount till the time the customer stays with Astra. Also, clients of the affiliates get a 5% lifetime discount on the listed price.
If both the use cases are applicable in your case, you can be both a Partner & an Affiliate. In that case, all the licenses you buy using your account would be eligible for an upfront discount and licenses bought using your unique Affiliate link would make you eligible to receive the applicable commissions.
Log in to your dashboard, go to your shop & your discount will be pre-applied. You simply need to make the discounted payment & license will be added to your account.
Note: The discount applied in the image is for representational purposes and may not be equal to the discount applied in your case. Actual discount applied would be as discussed with your account manager and based on the number of websites and the partnership tier that you belong to.