*UPDATED January 23rd, 2023!*
Shipping prices are listed in a chart below by weight of item and your general location.
Buyer only has to pay the actual postage costs as charged by the post office or less than actual postage - see ***.
I will combine items for one shipment to save on postage if possible - see list below. I usually can mail several items for the same rate depending on the combined weight. For International orders for 4oz. or heavier, it might be best to break the order into two or more parts and ship item by the cheaper letter rates.
Shipping materials are free and I use good quality envelopes, chipboard backing and other necessary protection for shipping. No additional handling charges.
I always use stamps for postage when mailing your order. I will use a mix of older U.S. stamps and maybe newly issued stamps as needed. *** Using discount U.S. postage allow me to pass lower shipping prices to buyers. 
Insurance and/or registered mail can be added at buyer's request and cost. Cost depends on your location.
I ship the same or first business day after receiving payment.
UPDATE - United States Postal Service changed rates January 22nd, 2023 and those below have been updated
The weight for each item is listed in the description. 
Combined shipment for postcards and covers: I can mail...
WEIGHT (oz.)     United States        Canada                Worldwide
        1                         $1.00               $1.85                   $1.85
        2                         $1.00               $1.85                   $3.00 - 2oz is the most common weight for an item
        3                         $1.00               $2.45                   $3.00
        3.5                      $1.00               $3.00                   $4.00       
*NOTE *  Everything mailed at 3.5oz and less is mailed at first-class letter rate. Over 3.5oz, it is mailed either parcel rate or large flats rate depending on size and volume. Please message me if you questions about large lots or large volume orders. USPS prices depend on your location and there's too many to list. I will always do my best to find the lowest cost shipping option from the USPS and buyer is never charged more than what's posted from the USPS. When in doubt, message me please.
 *PLEASE NOTE* International Buyers In some cases it might cost less to mail larger shipments in two parts at 3.5 ounces or less at the lower letter rates than one larger shipment at the parcel rates of 4oz. or more. I've always only charged for shipping the exact rates as charged by the postal service.
Basically, it's one ounce for each additional 6 regular sized covers/postcards I use the USPS website to calculate larger shipments by weight and your location. You can also use the USPS website to calculate larger orders or just ask me. Thanks!