How to graduate in an eco way?

No idea what is eco or not, all I know is that I graduated with the TT arkadia rifle on Halix, took a lot of Halix ;)

 

I've made some experiments to find that out shortly after the mentoring system has been re-introduced.
Never found the time to add something to the mentoring guide but iirc the results were suggesting either to engage in super-eco hunting (for Anatomy skill) or crafting Basic Filters (for Engineering skill). Might all depend on your current skill levels and style of playing but in general the most eco way to increase Anatomy/Geology/Engineering/ should also be the most eco path to graduation.

 

Cheapest and fastest is repair skilling on a warp ship, but there is 0 chance of loot back doing that.

Next would probably be carabok on arkadia for pure skilling speed.

But for me personaly I like doing activities that will likely break even or slight profit and for those I would recommend the Shy Vixens across from city of dreams on Rocktropia to sell the vixen gears (around 1000%) or the gateway punys on Calypso for bones (not sure what they are selling for but I know its high markup)

The other option would be mining which is how I did it way back in the day.
Rookie mine while walking for fruit/stones to cover for your losses. Once your bank roll is big enough to justify non rookie mining then switch to that, but make sure you are in markup areas to cover the losses since stones probably wont cover the loss on that.

Alternative is easy to get with rookie or standard mining on rocktropia and has a high markup.

For pure speed, tripple dropping the highest lvl mining amps you can on arkadia should push you through fast. (I did that with dclass amps a couple months ago working on my HP and ended up getting a tower :D but it is definitely the most expensive and risky approach)