I searched online and found plantogram sells 1.5 - 2ft tall Abiu ( they don't mention it being grafted so it is a seedling) for over $100 and then add shipping price to that.
There are local nurseries down here in South FL where i saw Abiu being sold in 3g. The plant looked like 1ft tall on a 3g pot and was being sold for $40. The tag is from ZHPP nursery. I contacted ZHPP and asked if they graft Abiu and they said all their Abiu are seedlings.
I am not a reputable seller and don't want to be in selling business but i saved some seeds from a good tasting Abiu we purchased during our fruit hunting trips. There is a youtube video we made of that Abiu -
https://youtu.be/fvRqgxL9InwAnd seedlings from that batch are now 3 months old and growing good, their root system gets extensive very fast so will need to up-pot them soon. If you want a few seedlings i can ship to you, i have listed them in my garden clearance sale post here.