Breakdown of sokukounyuu ga dekimasu.

Questions & Answers about sokukounyuu ga dekimasu.
It’s usually read そくこうにゅう.
- 即 = immediate / instant
- 購入 = purchase / buying
So 即購入 literally means something like immediate purchase or instant buying.
In online selling contexts, it often means buying right away without asking first.
This is a very common learner question.
In 即購入ができます, the verb is できます.
With できる, the thing that is possible is often marked with が.
So the structure is:
- 即購入 = immediate purchase
- が = marks the thing that is possible
- できます = is possible / can be done
That is why が sounds natural here.
Compare:
- 購入をする = to make a purchase
- 購入ができる = to be able to make a purchase
English learners often expect を because purchase feels like an object, but with できる, Japanese commonly switches to が.