Each seller do its own rule. Some sells right away even if you are not Testie (like Freak0 and Elmy), some won't. For most it is true that they prefer to sell to active members, and not just because you are here for 1 or 3 months, because they sell at cost.
Here for exemple I refuse to sell to non Test or non affiliate that are less than a month old and not active member, I have refused a few PMs (of random guys not in Test and non affiliate asking for an item and with 0 forum posts) and many discord requests because of that since I set up my shop. I could have made more sales if not for that, but org first. It's a dilemma in the end, because I can also get some nice item from people here at cost (and I have bought from ppl here quite a few times) so it is nice and fair to do the same in return.
But back to
@Wizzkid topic, there are quite some sellers here with the CCU you are looking for, but at least for the retaliator you should wait for sales this month.