Truth is, there isn't a lot of risk involved with investing. Well depending on where you invest.
While a large sum of money may be $500 to some and 10K to others, I'm not sure where you are going with this. But there are plenty of options.
My ausi perspective may be a little different to yours but here goes.
1. As safe as anywhere else, high interest accounts. ING happen to have accounts that are earning your 5.6% p/a. Nice little return. Ubank 5.71. You can get your money out at any time. Not bad really.
2. Term deposits. Yet again, just whack a large sum into a term deposit. Out of harms way from any notions of spending it for a short time. Around 5.21% pa from Ubank. But most large banks have these.
3. LEARN about the share market. Read some books, do some homework. Set up a share trading account and start off with one parcel ($500). Most fees involved here are around $20 per trade and are tax deductible. Hey if you have enough, do either 1 & or 2, and dabble with 1K investing in shares, learning along the way.
4. Property. Do your figures, if they stack up dive in. Maybe risker than other ways to earn some money. But I like to think of eventually getting rent as passive income once the investment has been paid off. One can dream....
1, 2 and 3 is where I would start though.