After giving hauling/courier missions a slagging off I've been doing a few of them to buy new bits for my hauler and I've found that if you are outside the original 55 system bubble of Beta 1 then you can make really good money in the more obscure systems especially between Independent and Federal ones.
Two screenshots below show one run between two such systems:
That's fifteen missions in one go which netted 49,433 credits. Not bad for 8 minutes work
Another wee tip is that the missions on the board refresh every 5 minutes. So for example 09:00, 09:05, 09:10....etc....etc so if you accept missions at 09:03 wait 2 minutes go back in and there will be another pile of missions for the same places. Watch the times and leave yourself enough room to get to your destination but sometimes if you wait 10 minutes you can treble or quadruple your takings on a single run!
I noticed this, too. I also got bitten by exiting the bulletin board to check where a particular system was, and when I went back after less than a minute, the job had gone