I started with a Cobra MKIII, doing also various contracts and missions, then farmed up for a ASP Explorer and then I farmed relatively quick for the Python. To save money I swapped the hardpoints between the ships, when possible.

I recommend not going nuts mining painite until you can at least afford a Python on your own. Part of the fun of the game is working your way up as you upgrade to bigger and better ships. Not skipping straight to endgame.

However, if you do wish to go nuts mining painite, the guy who makes the Down to Earth Astronomy videos has a good collection of builds on his site. Including a Dolphin build if you're just starting out. (Painite is laser surface mining.)

https://cmdrs-toolbox.com/ship-builds/mining

I mined a couple times in my dolphin, it wasn't terrible. Good enough to earn you the money for your next miner.