PaperHistory
Quality United States Postal History at a reasonable price. Stampless to 20th century; issues on cover, doane cancels, town postmarks, back of book, machine cancels, Confederate States and more.
Check individual items. Basic shipping is free on some items, and $1 on others (generally, consignment items). Over $30 I use a cardboard mailer for small items; over $50 I use tracking for domestic shipments (no charge for some items; $4.50 charge on consigment items). International postage is $2-3. There may be exceptions for bulkier items.
Shipping is by next business day and usually faster.