I was looking at twistedquarter.com but they want to charge over $10 on shipping for $8 worth of small bolts that could be shipped in a envelope. Any other places that won't rape you on shipping?
Yeah they fit in a small envelope but the weight of metal quickly adds up and you're probably past 11 ounces and pushed into their 1# rate which metered (not flat rate) would run over $5. (even 11 ounces runs $3 and must meet strange criteria about envelope aspect ratio, bendability, bunchability, thickness all those insane USPS rules)
Bob Roberts will typically stuff a bunch of stuff in a flat-rate USPS box. And I think he still has the smooth top carriage bolts.
And Bob's rates start at $7 since that's the cheapest 1# flat rate he gets through the post office.
Arcadeshop.com is where I order them.
And they will charge you $11 for UPS ground base.
In the end, shipping is very costly from almost anywhere. While some outright gouge intentionally, others just have no real options without having to offer tons that cost them more time and money. A lot of sites have a discount with a carrier and chose to use that one carrier based on their normal sized orders. If you dont meet the size you end up paying more, and it's not worth their effort to go do something that takes a lot more time/they don't have printers/labelers for/etc...
That's why many stick with UPS or FedEx ground, while Bob sticks with flat rate USPS. In the end, shipping almost anything is $7-$9 base now, with a rare $5 if you're lucky. Only a single small tiny item can go for under a $1 anymore.
The ONLY place I've ordered from lately that has reasonable shipping on tiny orders is PinballLife ($6 base) and GreatPlainsElectronics ($3 base) . Unfortunately neither sell smooth top carriage bolts.