Alternative step-based web forms for order / payment (instead of TypeForms) for self-funded startup?

Hi ya, (first time poster here)

myself and a co-founder are evaluating an existing product in a couple of growing markets. I want to make a web form that let's users choose products and place an order, while it's UX needs to be slick. This is to test our basic market assumptions.

Typeforms online shop template (https://template.typeform.com/to/adZWiq) is superb, because it also integrates with carrd.co (affordable presence/design) and Stripe (affordable payments), but we can't afford $420/yr.

Other form services I looked were trolley.link, Stripe's forms (both for self-funders), and a few "plain" forms (non-immersive - e.g. either all on one screen or kinda clunky transitions), but still looking for a more slick UX experience.

Then I looked at switching platform, from carrd.co stack to Wordpress "stacked" theme and/or WooCommerce, each seem~ to take a hit on overall cost or "slickness" (but I can't be sure..).

I guess this might be a common decision, so if you've any recommendations for this, I'd be much grateful.. :)

Cheers Pete | @Yesnow