Each advertiser is also mailing his copies to his customers or mailing list, and every last copy mailed has YOUR ad in it. So, usually within about ten days after your ad appears in print, you will start receiving letters with quarters in them asking for your Big Mail. Some advertisers, for one reason or another, are quite slow in mailing their copies, but this can work to your advantage. You will want to include them in every one of your Big Mails. Pal Clubs, etc., etc.
Wholesale firms supply commission circulars to mailorder dealers, usually at cost.
He then sends the balance, along with his shipping label, to the wholesaler, who drop-ships the order directly to the customer under the dealer's shipping label. You will soon learn that gift items and general merchandise rarely appeal to people who are ordering Big Mails, unless you are offering them on a wholesale basis. If you work at it, you can make a lot of extra money by including good commission circulars in your mails. Test a few hundred copies of each commission circular. If it evokes no interest, discontinue it.