I am looking for a place where I can buy new or refurbished desktops,
laptops and computer parts cheap enough to be able to re-sell on eBay
for a profit.

Companies located outside of the U.S.A. are fine as long as they are legitimate.

When computers etc come off lease they are sometimes auctioned off in large
quanity.  You can buy below wholesale, but need to be able to trouble
shoot and repair.   Test equipment and computers go on the block when
various firms merge or go bankrupt.