The Ships Market is where you can buy ships
The daily limit that you can buy is related limited to your bases production capacity for 24 hours, except the speed universe where the limit is doubled (48 hours)
The daily limit also increase by your account total experience, in the percentage to the game universe top xp player. The top player will have 100% extra limit, and you will have it proportionally to him/her.
Its up to you to get that 100%!!
The ships prices are related to your account level, 75% + level, so if your level is 10, you will buy the ship original cost +85%.
At level 100, it will cost you +175% (example for a fighter, 5+175% = 13.75 rounded up to 14 credits)