Yeah, for housing multiple snakes, racks is by far the cheapest. Though if you're only ever going to have a couple, then they don't make sense. And some people like to have their animals on display as well. So it's really about what fits your needs the best.

I personally have a mix of racks and display vivs. I like to show mine off - I rotate who's in the display viv every couple of months. This way I get to show all of my snakes off at some point or antoher.