Having just tried Gamma for first time I see I only have 100cr - is that correct as how can I do anything with that?
Well made a couple of hundred on a run so guess it will be a very slow start.
Check out the bulletin board for any local/short range courier missions, but remember to check how much time is left. You can easily earn hundreds to a couple of thousand credits in half an hour.
Courier missions from the bulletin board should get you started. Together with selling exploration data (depending on where you started), it brought me up to 13.000 CR within an hour.
(And that's probably a pretty bad rate for any experienced players but I'm quite happy with it. )
Courier missions or scan a couple of solar systems with your discovery scanner. I made my first major purchase a fuel scoop so I'd never have to worry about running out of fuel. From there, keep picking up courier missions and scanning each system they take you too. After a few systems I was able to buy an upgraded FSD for the sidewinder which nearly doubled my jump range.
I've done this for several nights now, playing just an hour or two each night and have just enough to buy a hauler as of last night. It's slow but steady. Hang in there!
I always like to do a courier mission straight off the bat for a couple of hundred credits just to get some pennies in the kitty for fuel and repairs etc, then go exploring scan a few suns and stars which can sell for a couple of grand each.
Once I have a few grand I go back to the space stations and begin doing courier missions again
I quite liked the shoestring start like in Elite 1984.
It took me 2 or 3 trade runs to convert 100Cr to 650Cr. Mind you, on that first run, you have to choose a cheap commodity that costs less than 100Cr
You can always cheat (compared to original Elite) and do some of the tasks mentioned. I later did a 4Ly legal courier run and earned 3800Cr, which made a mockery of all my hard trading work...but at least I know I could build a business with just 100Cr.
I was a bit bemused by that 100cr at the start of gamma myself. However, as soon as I opened the Bulletin Board and saw a couple of 1000-4000 credit missions, I felt much better.
I just strip my Sidewinder of guns and scanner, saving 6 tons, and began playing the trader. Starting with 100cr not as bad as it seems at first glance.
Don't panic! I started with simple courier missions and I know have 26,000 credits for a few hours work. It's not difficult you just have to stick at it. Check the bulletin board and select the highest paying mission that you can jump to. Rinse and repeat. Once you have some money you can top up the courier missions with some cargo of your own.
Depending on where you start, people have reported not being able to do any missions at all. If thats the case, explore. Scan unknown stars and planets. You'll be surprised what you can earn with exploring. I've had amounts over 10k for one system. I've seen screenshots of one cmdr with 57k for one system.