grind dilithium, buy eight unreplicable materials a day, pop them onto the exchange and you can get about 45k-65k each (avg 400k per day). Also grind data samples, buy alien artifacts off the exchange and convert to power alien artifacts. 400-600k per profit every four hours. Look for support efforts in colonial regions, get refugees 120-280k per doff. doff trade missions for gamma quadrant commodities can get you anywhere from 60k-150k per batch. Doff officer cadre from the academy can get you about 200k. last week I've casually popped all those on the exchange and netted about 20 mill easy. Which is I think 1/2 the price of the antiproton mag.
Don't be afraid on the exchange to buy something that is posted at a price lower then the rest of the items and reposting it at the correct price. Also STF elite get you 1k per run.