Since you say you will probably emigrate in the future, I would advice you to stay away from anywhere your money gets locked in for any significant duration. Having your money locked in will do nothing but reduce your options. Find ways to invest that don't result in your money being locked in.
Real estate can provide reasonable (but not stellar) returns over a moderate to long term, but it's illiquid, potentially risky, and requires upkeep (which costs money). If you are purchasing to use as a primary residence, will you still want to live in the same house in, say, those 25 years? If the country "doesn't look good" some time down the road, will you be able to sell and recoup the money you put into the house? (Not just the capital cost, but also interest, taxes, maintenance, etc.) I'm not saying don't buy real estate, but I would advice caution, and to not buy it solely as an investment vehicle. If you buy a house and earn a bit of a return on it, that's great; but you should buy a house because you need or want a house, not because it will earn you a return.
With those two out of the way, the big winner for long-term investing is usually stocks. Generally speaking, over reasonably long periods of time, which is to say something like five years or more (this is your investment horizon), it's hard to go wrong with a diversified international portfolio of cheap stock index mutual funds. That's a mouthful, so let's pull it apart.
- diversified – Don't put all your eggs in one basket. Find a few different options, markets, etc., and spread your money between them. One easy way to do this might be to locate a global market index stock mutual fund, or you can put together a portfolio yourself. Don't go overboard; four or five good choices should be enough to have you well covered.
- international – There's a reason why your bank is paying 5-8% interest, and it's probably related to inflation (as you say). By investing outside of your own country, you reduce the impact of local investments losing their purchasing power over time compared to those of other countries. As long as you stay in your country, this might even work out in your favor. Broadening your horizons beyond the borders of your own country also reduces risk, since the risk of an economic downturn in one country at any one time is usually higher than the risk of a world-wide simultaneous economic downturn.
- cheap – Look at that expense ratio. Keep it as low as you possibly can for the type of investment you're making. You can't be sure about future returns, but you can be sure about the cost. For some parts of your portfolio, it may be necessary to pay a bit more to get access to those markets; for example, where I am, mutual funds that invest in Asia or "emerging markets" tend to be a lot more expensive than those investing in the European or North American markets. Having some money in those markets may still be worthwhile, but that's no excuse to not shop around for a good deal for what you're buying. If you can get the same result for a 1% cost instead of a 2.5% cost, you probably should choose the 1% alternative for that market even if you can get access to other markets for, say, 0.2% cost.
- stock – On the whole, the stock market is more volatile than, for example, the bond market. However, unless you need the money within the next 2-3 years or so, you have a much better chance of making a good return in stocks than in bonds.
- index – Index investments attempt to simply track an established index as accurately as possible. For example, you could invest in something that tracks the US S&P-500, or the UK FTSE-100, or some other large stock market index. You won't do better than that index by doing so, but you also won't do (significantly) worse than it does. Stock picking is difficult, and it's virtually impossible to keep picking stocks that outperform their relevant index, so you generally have better chances of making a good return by not even trying to play that game.
- mutual funds – ETFs (exchange-traded funds) can also work. This is just about how you invest the money. Mutual funds have the advantage that their transaction costs tend to be reasonably low, which is an advantage if you are investing a little money at a time. Again, look at the cost; that, and your investment amount, are the only two factors you can be certain about.
You say that you feel it would be "a big gamble for someone with no knowledge in investing", but that's why you should go with index funds; not only do they tend to be cheaper (often considerably so) than actively managed funds, but they also reduce the element of choice to basically "which country's or region's stock market do I want to track?". If you answer that by spreading the money around the world, then even though there will still be years when you get a low or possibly even a negative return, you'd probably have to outright work at it to match the around 0% yearly return you can expect to get from a good bank account on a time frame of more than a few years.
