Buy it (50 EUR is almost free!) and grab some cheap-but-OK probes to start with. I'm not sure what the current budget recommendation is here, but you probably don't need the fanciest probes to begin with, and even if you end up needing nicer passive probes in the future you'll still have some cheap spares.
You're not going to get a useful 500MHz out of passive probes in many circumstances (sit down and work out what loading 10pF@500MHz is to your circuit, and that's not even thinking of ground lead inductance etc!). The 500MHz bit will be most useful with 50ohm sources (e.g. active probes), but the key is that you don't _have_ to use these until you need the bandwidth, whenever that is.
Worst case if it's not doing what you need or is too big or something then you can pass it onto someone else without losing anything given the low low starting price.