A car that cost 3 million yen when new is apparently only worth about 300,000 yen now, so I think I'll keep driving it a bit longer.

Literal

New-car-time 3-million-yen cost car [even-も] now [topical-では] about-300,000-yen [hearsay-だそうですから], a-little-more drive [intent-おうと] think.

A practical money observation. 新車時 ('at new-car time') is a compact compound. 300万円した ('cost 3 million yen') uses した (past of する in its 'to cost' sense). 今では ('as things stand now') marks the current contrast. ~だそうですから ('since I hear that...') combines hearsay そうだ with the causal から. もう少し乗ろうと思います ('I think I'll drive it a bit longer') uses the volitional + と思う pattern for personal intent.