[ashappard]

yes, you can certainly buy without 25 posts.

itrader :

to the left of a post - in the area where the poster's avatar/post count etc. sits, you will see some text saying 'iTrader Ratings' with a number beside it. Thats the number of feedbacks the user has received. It is also a hyperlink into the itrader system, specific to that user. Click it when you have completed a transaction with a buyer or seller, and you will see another hyperlink saying 'Submit feedback for <username>'. Click that, fill out the form, and submit.

feel free to ask questions if needed, and iTrader can also be used to see how a seller or buyers feedback look before you deal with them.