Yes you can start trading as soon as you’ve been assigned a LETS number. You start off with 10 greenies and you can earn more by offering stuff, and of course you can “buy” bits too.
Once a transaction has been agreed simply pm Earthmummie MK with the details (cc’ing the person you’ve traded with) and remember to include theirs and yours LETS numbers.
Regarding postage you can either include the cost in the greenies you ask for, ask for a few extra greenies on top of the asking “price” or you can ask for postage to be covered with cash (gifted paypal is an easy way). It is helpful too, once the transaction is complete, you’ve received your goods that you just pop on a bit of feedback .
HTH
Joxy.