I am nearly at the end of the game, I won't give spoilers but when you have to buy a tool to hack second space ship shield generator which is 100 credits, I don't have enough credits left and it isn't easy to find that much credits, does slot machines in gambling area works and can you win something there otherwise where can I get more credits? thanks :)

yes, you will either win 4 nanites or lose 2, so with a bit of patience, and a lot of quicksaving and quickloading, you should have the required 100 nanites in a couple of minutes.