I want to start investing money and build a portfolio.

I read a lot of things about investing, videos, guides, etc... and summing up we need to start with some amount and the best would be to constantly continue investing every month.

Imagine this:

  • I will start an investment portfolio with 1000€ and buy 10 "stocks" of some company for 100€ each... (ignore that this is a action, is just for example);
  • Next month I save 100€ to invest and buy another "stock" for 100€;
  • Now I have 11 "stocks";
  • Next month the "stock" rise up to 101€;
  • Now I have another 100€ to invest but... what to do now?

Should I buy another "stock" that costs 100€ or less?


Should I wait another month and have 200€ to buy that 101€ "stock"?

This is the only thing that I can't understand... Maybe I need to save every month 100€ to invest when the "stock" cost drops and only buy when its on sale and not buy every month?

  • Look into mutual funds - they make it easier to invest fixed amount.
    – void_ptr
    Commented Nov 6, 2020 at 18:34
  • 1
    Just to help with clarification, if you buy 10 stocks, that means investing in 10 different companies... as compared to buying 10 shares of a single stock/company. Commented Nov 6, 2020 at 19:00
  • @BobBaerker I know that, thank you! It was just for the example ;)
    – Kiril1512
    Commented Nov 6, 2020 at 19:23

3 Answers 3


I'm not sure what you mean by "action" - it sounds like you use it as a generic term for some investment like "stock", so correct me if I misunderstand, but I'm going to assume you mean something like a "stock" or a "fund".

The price you pay doesn't matter a whole lot (other then limiting whether you can buy the minimum number of units). What matters is what you think the return will be. A stock that goes from 10€ to 12€ has the same return as one that goes from 100€ to 120€ (assuming you buy 100 of the former and 10 of the latter).

So should you buy more stocks at 101€? Well that depends on whether you think it will continue to go up in value. Obviously you can't know for sure, and you don't know if other stocks with a lower price will necessarily rise more.

Maybe I need to save every month 100€ to invest when the action cost drops and only buy when its on "sale" and not buy every month?

This is called "timing the market" and is not an effective strategy. Certainly buying stocks at lower prices is better, but what if the stock never goes back below 100? If it keeps going up, then obviously you should have bought at 101 and rode it up.

If you have money to invest, just invest it. Sometimes you'll get lucky and buy low, sometimes you'll buy high, but since markets tend to go up over time, on average you'll have more winners than losers. This is called a "Systematic Investment Plan" and is a common way to implement "Dollar Cost Averaging", where you buy stocks periodically, averaging out your cost by buying at various prices.

If you are new to investing, then it's usually recommended not to invest in individual stocks. You can significantly reduce your risk buy picking a few broad mutual funds rather than trying to get lucks on individual stocks.


If you literally mean that you have 100€ and can't buy a whole unit of X that costs 101€, that's another reason to focus on mutual funds or ETFs that allow fractional units rather then individual stocks. You can invest any amount you want (the unit price is largely irrelevant - focus on returns) and don't have to worry about buying whole blocks or units

  • Thank you for your response. Yes when I say action I mean "stock" or "funds" or "etf's". I will edit my question to correct that term...
    – Kiril1512
    Commented Nov 6, 2020 at 15:57
  • An appropriate word would be positions not actions. Commented Nov 6, 2020 at 16:00

Look up "Dollar Cost Averaging" (regardless whether you use USD or EUR, this is about the principle). Basically: If you wait, you invest and TIME THE MARKET. Timing the market is a GREAT way to earn more. It also is a skill that VERY FEW people have, and mostly it is not available to you. If it is, you are way better of to make a career doing that and having 100 times more money available. People that CAN time the market are RARE and earn.

Now, assuming you can not time the market - do an action every month. See, who says that after going to 11 it will not go on to 12, 13, 14. Look up the historical stock prices of companies like Yahoo, Apple, SAP to realize how far prices can go over years.

Hence Averaging.

  • Ok so you are saying to go buy every month, but if I have only 100€, I can't go buy the same stock that is worth 101€ now...
    – Kiril1512
    Commented Nov 6, 2020 at 15:37
  • 1
    Ah, but normally you buy cheaper stocks and MORE of them. Then you just buy a little less. 9 instead of 10.
    – TomTom
    Commented Nov 6, 2020 at 16:20

If you are investing 100- per month, it is not possible to buy "individual stocks".

You should buy an index fund.

  • 1
    You have so many stocks lower than 100€, you can see Intel stocka as an example:38€
    – Kiril1512
    Commented Nov 7, 2020 at 16:34
  • 1
    hi @Kiril1512 , sorry, no. You cannot buy individual stocks if your budget is 100- a month. (In your example, you'd be buying "2" intel shares .. and then have money left over.) You'll have to set the idea aside. Buy an index fund.
    – Fattie
    Commented Nov 7, 2020 at 21:49
  • Ok, thank you for help @Fattie :)
    – Kiril1512
    Commented Nov 8, 2020 at 15:08

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