Yes. eSIMAdvice currently lists 12 Stixrs Cuba plans.
The cheapest Stixrs Cuba plan is Cuba · 1 GB · 3 days · 4G · Fixed, at $22.05.
Cuba · 3 GB · 3 days · 4G · Fixed has the lowest price per GB right now: $18.00/GB ($54.00 in total).
Yes. The prices shown already include the AFFINCO coupon where it applies.