So I was trying to implement DHCP snooping on all switches in packet tracer, with no success. I don't know if I should buy a couple 3560s or just find another option

In addition, I know that the ASA 5505 is also going to be a part of several labs on this certification as well, and I've heard GNS3 is an option, but I've also been told to go just buy one. As they are like $250, It's a questionable investment.
What do you guys think? It's not that I don't have the money, I'm just cheap