How to buy marijuana without fakes and long waiting time?

Where in Prague can you buy marijuana without long waits and the risk of coming across a fake? This is important because, of course, you want to buy a quality product that meets the stated characteristics. I've heard that there are several services and stores that sell cannabis, but I'm not sure what to rely on and where there is a risk of buying something wrong. I've been looking for information online, but I don't want to fall for any questionable offers. Who can share some verified information?