Solo does not currently support a shopping cart for ecommerce or payments but many customers create payment links in Paypal or Stripe or other and then include those links in their Solo website. When a customer clicks this link on your Solo website, it’ll open a Stripe or Paypal payment page in a new tab in their browser. To add a custom link in your Solo website, see this help article.

See Stripe instructions for creating a payment link.

See Paypal instructions for creating a payment link.

If you need advanced ecommerce control of your website, you can consider embedding Shopify into your Solo website.