hi and welcome to the forums! so cycling is when people time travel in game in order to move out villagers. a lot of people have "cycling towns" where they either do it on their game or another one that they bought. there's tons of methods as to how to cycle, you can probably find them via google or something. in terms of selling villagers, people tend to sell super desirable villagers such as rosie or beau for lots of in game bells or even in some chances, bell tree bells (tbt or btb). when a villager is in boxes people go to the villager cycling forum and post that they're selling that villager, then the buyer goes to their town and talks to that villager to get them to move to their town. i hope this helps!