Hi Kyra,
Thanks for reaching out to the Adobe Stock community.
We've discontinued the single image purchase option for all the users. The smallest subscription plan which you can purchase is the 3 standard assets a month which can be cancelled at any time and does include an annual commitment.
I understand your requirements for the Stock images and since there is no such plan available as per your requirements, I would suggest you to check out credit packs offer.
Currently, the most flexible option is to buy a pack of 5 credits, which can be used to license 5 standard images any time over the next 12 months.
You can check the pricing for credit packs here: Adobe Stock pricing and membership plan | Adobe Stock
Additionally, I would also suggest you to go through Common Questions, Adobe Stock and Stock Licensing & terms FAQ: Where can I find the terms and licensing information for Adobe Stock? to understand the licensing terms and restrictions of Adobe Stock.
Feel free to update this thread in case of any additional questions.
Regards,
Twarita