does a usa .3 stamp conestoga wagon have any value and an audubon american artist stamp with birds of paradise I think they are blue birds .5 us postage at the very bottom,and a .10 stampwith two flags and the words united states at the bottom also it is attached to clipping of the envelope it was mailed with the postmark on the clipping has us postal service 476 -pm 22 jul 1975

There is a Conestoga Wagon one listed on the following link.

Conestoga Wagon-1800's-Stamp-1988 - eBay (item 180224359594 end time Mar-22-08 13:37:33 PDT)

It doesn't look to be in the best of shape though. I am sure that one that would be in perfect condition would be worth at least somewhat more than what they are listing that one as.

I'll check on the other ones. But, someone else might come along who might also offer assistance here.