A Rich Barsteward mate of mine says that if you want to make money the first thing you have to do is stop working ... then you a) have time to make investments and b) incentive - to survive!
- Pay off all your debt
- Stay out of debt
- Buy a house (OK, you are going to need a mortgage for that)
If you are able (skills and "an eye for") to buy a house cheap and do it up, and then move on, the tax advantages are significant (no capital gains tax on the your primary residence).
If you can do the house up, AND have accumulated enough to buy another (and retain & rent out the first) even better.
Skip spending money on depreciating assets, like cars / holidays / drunken nights out until you can afford it from spare cash.
I didn't do any of that
, I had a succession of sports cars etc. in my 20's, and was self employed I bought the cars cheap - e.g.a Lotus Esprit that a Porsche and Ferrari dealer had taken in Part Ex and stood on their forecourt for months ... I made them a ridiculous offer and they took it ...
You could invest your spare £100 a week in Tesla (using an ISA). its a one-way-bet. if Tesla do well you sell the stock and buy a car. If Tesla tank you won't want the car anyway ... but its a gamble, not shrewd investment and, as of today, you are "late to the party".
Why not? A million is not a lot these days. Seems like a reasonable target to me. The conventional maths aren't great though:
£100 a week invested at a high rate of return is 40 years to £1M
The first 7 years get you to £50K ... enough for a posh car perhaps (although inflation will have eaten some of that ... but your investments can increase, with your salary ... but the money you put in early will grow the most). Its a long wait for the car ... but a reasonably approach to a Pension.
Clearly you need a strategy that doesn't take as long, and the more you put in, and lock away, on day one will work the hardest for you.
People who I know who have made money (who didn't Inherit, Marry or Win it ... or do all three!) work hard, and have their own business, and obviously more than 50% of their decisions were good ones ... but IME that route is pushing a tax-rock uphill, so what you ought to take-home and actually do are different things, so its no quick win either. But I reckon its the route with the most likely upside
Having Kids is an expensive project. If you have your own business by then my advice would be to find a wife who will, also, run her own business. With enough earnings you can pay other people to do the humdrum ... with a conventional wage any earnings will go on the cost of child-care whilst at at work ...