What if?

  1. The question

    What if I invested the money I spent on my car?

    Treat a round $150/week as a car payment and put it in the S&P 500 since 2018. A proxy for “the car,” not a used-car price index.

  2. Assumptions

    What this page actually assumes

    • $150/week stands in for a car payment — insurance, fuel, and the loan mashed into one round number. We do not have a table of actual car prices.
    • That cash buys the S&P 500 every week and is never sold.
    • Default start is 2018 (a typical loan window). 2015 is available if you want a longer habit.
    • This is not advice to skip owning a car.
  3. Historical data

    2018-01-052026-08-28

    Same S&P 500 Friday series as the other stories. Shorter starts mean fewer payments and less time in the market. There is no CPI car-depreciation overlay.

    Series: S&P 500. Same contribution calendar. No data before 2015.

  4. Interactive simulation

    Change the habit, stay on the real curve

    $500/week · S&P 500

    2018-01-052026-08-28 · $500/week · S&P 500

    Contributed$226,000
    Held to the last date$469,682
    Return+107.8%
    SteadyGrow value$653,009
    vs blind DCA+$183,327
    S&P 5002018-01-05 → 2026-08-28 · $500/week
     +$183,327 vs blind (+39.0%)Ended +39.0%
    Blind DCASteadyGrow
    $0$171k$342k$513k$684k2018-012019-092021-062023-032024-122026-08
  5. Results

    What the numbers say

    Ending value is “what those payments became if they had been index shares.” Compare it to what you actually got from the car: transport, not a return.

  6. What changes if…

    Nearby questions

    What if the weekly amount wasn't always the same?

    These pages fix the contribution. SteadyGrow keeps the same long-term budget and sizes weeks from valuation — more when markets are cheap, less when they're stretched.