I have an idea to start mining altcoins (Zcash, Monero or something like that). At the same time I'm not going to spend my money on ASIC equipment.
Can I make any profit on GPU money? Or is it an idiotic idea now?
Profit is a relative term. If I told you that you can make $0.20 per day of profit per GPU would that be enough for you? For some maybe, for most not so much.
Zcash actually has ASICs already so that is out. ETH is half ASIC and half GPU. XMR is more geered towards higher end CPUs.
So your best bet is to mine ETH. Currently with a RX 580 8GB which you can buy second hand for like $100 will net you $0.20 per day per card. Your choice if you think its worth it.
Keep in mind if ETH goes down in value you make even less. This is assuming you have $0.10 kwh power.