[When someone bids, is the seller picked randomly?]

I believe that if there are multiple equivalents then the sales are random.  Example:  I put up a handful of offers of common salvage at 5.  I find that I’ll sell one or two from each block of ten rather than the first ten selling first, etc.

[Changing rarity via converters]

I cannot understand why converters are so cheap.

[When someone bids, is the seller picked randomly?]

I believe that when there are two or more eligible bids for an offer or two or more eligibility blue offers for a bid it is random rather than by when the bid or offer was made.

[Adventures in Marketing]

The thing I’ve noticed about this server is that profit margins go away very quickly and that people are willing to work for almost nothing.