@arjunchahal I like where your head is at. Yes, you are making moves in the right direction.
Now let’s take a look one step at a time …
In the purchases database: make the plan ID the reference field, and the member ID can be a regular text field.
Connect your repeater to Purchase database. As you connect your elements, you will now see the purchase plans reference fields as options to connect to.
Now you are ready to create a dataset filter on the purchase dataset that is connected to your repeater. Get the current member ID and search for matching member ID field in the dataset. (Do not search for owner. The event code will make the Admin as owner of the record.)
So … how did you do? 