In the last few years we’ve seen a increase in eBay fees, sales and income taxes being implemented. Shipping costs to send a fuel tank out are close to $52.00 for a single box and UPS Ground service. I normally double box freshly painted items. It has caused bikes that could potentially be completed in two weeks to remain on the hoist much longer. I don’t mind my own bikes taking a year to complete, or nearly complete a restoration, but having a customer bike all summer makes a customer just consider purchasing something else. I was buying carburetors for much less very recently - than I can conceive selling them for with new parts. A brass 248 float alone could bring $50.00. 

What material changes are effecting your projects?

asco

I've felt for a while that USPS have been taking the pi**, particularly when sending small to medium sized parcels overseas. Fleabay's own Global Shipping Programme is much cheaper, and also much easier for the seller - they just post to a hub in their own country. 

Posting a fuel tank within the UK would cost about a tenner, although I accept that our landmass is a little smaller than yours!

Regarding selling fees, I usually just wait for one of fleabay's cheap selling offers before listing anything.